Possible NPE in CacheUtils.getMultimoduleRoot

### Affected version

1.2.2

### Bug description

When a project with maven-build-cache-extension enabled is imported into Eclipse with m2e I run into the following NPE:

```
java.lang.NullPointerException: Cannot invoke "java.io.File.toPath()" because the return value of "org.apache.maven.execution.MavenExecutionRequest.getMultiModuleProjectDirectory()" is null
at org.apache.maven.buildcache.CacheUtils.getMultimoduleRoot(CacheUtils.java:106)
at org.apache.maven.buildcache.xml.CacheConfigImpl.initialize(CacheConfigImpl.java:160)
at org.apache.maven.buildcache.RemoteCacheRepositoryProvider.(RemoteCacheRepositoryProvider.java:46)
```

Although from the javadoc it is not clear if `null` must be expected as return value from [`MavenExecutionRequest.getMultiModuleProjectDirectory()`](https://maven.apache.org/ref/3.9.15/maven-core/apidocs/org/apache/maven/execution/MavenExecutionRequest.html#getMultiModuleProjectDirectory()) there should be no unconditional dereferencing in https://github.com/apache/maven-build-cache-extension/blob/8b89d01c97b5d2b69e2fd06d8f4ddc33eb6d1fd5/src/main/java/org/apache/maven/buildcache/CacheUtils.java#L115

The full stack trace is
```
at com.google.inject.internal.InternalProvisionException.toProvisionException(InternalProvisionException.java:251)
at com.google.inject.internal.InjectorImpl$1.get(InjectorImpl.java:1104)
at org.eclipse.sisu.inject.Guice4$2.get(Guice4.java:184)
at org.eclipse.sisu.inject.LazyBeanEntry.getValue(LazyBeanEntry.java:71)
at org.eclipse.sisu.plexus.LazyPlexusBean.getValue(LazyPlexusBean.java:48)
at org.eclipse.sisu.wire.EntryListAdapter$ValueIterator.next(EntryListAdapter.java:102)
at java.base/java.util.AbstractCollection.toArray(AbstractCollection.java:148)
at java.base/java.util.ImmutableCollections.listCopy(ImmutableCollections.java:191)
at java.base/java.util.List.copyOf(List.java:1191)
at org.eclipse.m2e.core.internal.embedder.PlexusContainerManager$PlexusComponentLookup.lookupCollection(PlexusContainerManager.java:362)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.executeParticipants(ProjectRegistryManager.java:824)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.lambda$15(ProjectRegistryManager.java:800)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:462)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:342)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:281)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.lambda$14(ProjectRegistryManager.java:799)
at java.base/java.util.HashMap$Values.forEach(HashMap.java:1074)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.lambda$11(ProjectRegistryManager.java:797)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:462)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:342)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:281)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.readMavenProjectFacades(ProjectRegistryManager.java:769)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:396)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:370)
at org.eclipse.m2e.core.internal.project.registry.ProjectRegistryManager.refresh(ProjectRegistryManager.java:322)
at org.eclipse.m2e.core.internal.project.ProjectConfigurationManager.updateProjectConfiguration0(ProjectConfigurationManager.java:388)
at org.eclipse.m2e.core.internal.project.ProjectConfigurationManager.lambda$3(ProjectConfigurationManager.java:340)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:462)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:342)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:281)
at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:1100)
at org.eclipse.m2e.core.internal.project.ProjectConfigurationManager.updateProjectConfiguration(ProjectConfigurationManager.java:339)
at org.eclipse.m2e.core.ui.internal.UpdateMavenProjectJob.runInWorkspace(UpdateMavenProjectJob.java:80)
at org.eclipse.core.internal.resources.InternalWorkspaceJob.run(InternalWorkspaceJob.java:43)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
Caused by: java.lang.NullPointerException: Cannot invoke "java.io.File.toPath()" because the return value of "org.apache.maven.execution.MavenExecutionRequest.getMultiModuleProjectDirectory()" is null
at org.apache.maven.buildcache.CacheUtils.getMultimoduleRoot(CacheUtils.java:106)
at org.apache.maven.buildcache.xml.CacheConfigImpl.initialize(CacheConfigImpl.java:160)
at org.apache.maven.buildcache.RemoteCacheRepositoryProvider.(RemoteCacheRepositoryProvider.java:46)
at org.apache.maven.buildcache.RemoteCacheRepositoryProvider$$FastClassByGuice$$-732420573.GUICE$TRAMPOLINE()
at org.apache.maven.buildcache.RemoteCacheRepositoryProvider$$FastClassByGuice$$-732420573.apply()
at com.google.inject.internal.DefaultConstructionProxyFactory$FastClassProxy.newInstance(DefaultConstructionProxyFactory.java:82)
at com.google.inject.internal.ConstructorInjector.provision(ConstructorInjector.java:114)
at com.google.inject.internal.ConstructorInjector.access$000(ConstructorInjector.java:33)
at com.google.inject.internal.ConstructorInjector$1.call(ConstructorInjector.java:98)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:109)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:124)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:66)
at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:93)
at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:300)
at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
at com.google.inject.internal.SingletonScope$1.get(SingletonScope.java:169)
at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:45)
at com.google.inject.internal.BoundProviderFactory.get(BoundProviderFactory.java:58)
at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
at com.google.inject.internal.SingletonScope$1.get(SingletonScope.java:169)
at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:45)
at com.google.inject.internal.InjectorImpl$1.get(InjectorImpl.java:1101)
at org.eclipse.sisu.wire.BeanProviders$7.get(BeanProviders.java:149)
at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:86)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.provision(InternalFactoryToInitializableAdapter.java:57)
at com.google.inject.internal.ProviderInternalFactory$1.call(ProviderInternalFactory.java:67)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:109)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:124)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:66)
at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:62)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.get(InternalFactoryToInitializableAdapter.java:47)
at com.google.inject.internal.SingleParameterInjector.inject(SingleParameterInjector.java:40)
at com.google.inject.internal.SingleParameterInjector.getAll(SingleParameterInjector.java:60)
at com.google.inject.internal.ConstructorInjector.provision(ConstructorInjector.java:113)
at com.google.inject.internal.ConstructorInjector.access$000(ConstructorInjector.java:33)
at com.google.inject.internal.ConstructorInjector$1.call(ConstructorInjector.java:98)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:109)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:124)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:66)
at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:93)
at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:300)
at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
at org.apache.maven.session.scope.internal.SessionScope$CachingProvider.get(SessionScope.java:116)
at org.apache.maven.session.scope.internal.SessionScope.lambda$scope$0(SessionScope.java:92)
at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:45)
at com.google.inject.internal.FactoryProxy.get(FactoryProxy.java:60)
at com.google.inject.internal.InjectorImpl$1.get(InjectorImpl.java:1101)
at org.eclipse.sisu.wire.BeanProviders$7.get(BeanProviders.java:149)
at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:86)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.provision(InternalFactoryToInitializableAdapter.java:57)
at com.google.inject.internal.ProviderInternalFactory$1.call(ProviderInternalFactory.java:67)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:109)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:124)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:66)
at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:62)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.get(InternalFactoryToInitializableAdapter.java:47)
at com.google.inject.internal.SingleParameterInjector.inject(SingleParameterInjector.java:40)
at com.google.inject.internal.SingleParameterInjector.getAll(SingleParameterInjector.java:60)
at com.google.inject.internal.ConstructorInjector.provision(ConstructorInjector.java:113)
at com.google.inject.internal.ConstructorInjector.access$000(ConstructorInjector.java:33)
at com.google.inject.internal.ConstructorInjector$1.call(ConstructorInjector.java:98)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:109)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:124)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:66)
at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:93)
at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:300)
at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
at org.apache.maven.session.scope.internal.SessionScope$CachingProvider.get(SessionScope.java:116)
at org.apache.maven.session.scope.internal.SessionScope.lambda$scope$0(SessionScope.java:92)
at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:45)
at com.google.inject.internal.FactoryProxy.get(FactoryProxy.java:60)
at com.google.inject.internal.InjectorImpl$1.get(InjectorImpl.java:1101)
at org.eclipse.sisu.wire.BeanProviders$7.get(BeanProviders.java:149)
at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:86)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.provision(InternalFactoryToInitializableAdapter.java:57)
at com.google.inject.internal.ProviderInternalFactory$1.call(ProviderInternalFactory.java:67)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:109)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:124)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:66)
at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:62)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.get(InternalFactoryToInitializableAdapter.java:47)
at com.google.inject.internal.SingleParameterInjector.inject(SingleParameterInjector.java:40)
at com.google.inject.internal.SingleParameterInjector.getAll(SingleParameterInjector.java:60)
at com.google.inject.internal.ConstructorInjector.provision(ConstructorInjector.java:113)
at com.google.inject.internal.ConstructorInjector.access$000(ConstructorInjector.java:33)
at com.google.inject.internal.ConstructorInjector$1.call(ConstructorInjector.java:98)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:109)
at org.eclipse.sisu.bean.BeanScheduler$CycleActivator.onProvision(BeanScheduler.java:191)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:117)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:66)
at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:93)
at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:300)
at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
at org.apache.maven.session.scope.internal.SessionScope$CachingProvider.get(SessionScope.java:116)
at org.apache.maven.session.scope.internal.SessionScope.lambda$scope$0(SessionScope.java:92)
at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:45)
at com.google.inject.internal.FactoryProxy.get(FactoryProxy.java:60)
at com.google.inject.internal.InjectorImpl$1.get(InjectorImpl.java:1101)
... 33 more

```

Start in src/main/java/org/apache/maven/buildcache/CacheUtils.java at getMultimoduleRoot, then follow its call from CacheConfigImpl.initialize. Reproduce the Eclipse m2e import scenario with a null MavenExecutionRequest.getMultiModuleProjectDirectory() value; done means the extension no longer throws the reported NullPointerException during import.

Written by the indexing model from the issue text.