Can't run Grails 4 app with Digest Authentication

Thanks for reporting an issue for grails-spring-security-core. Please review the task list below before submitting the
issue.

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### Task List

- [x] Steps to reproduce provided
- [x] Stacktrace (if present) provided
- [ ] Example that reproduces the problem uploaded to Github
- [x] Full description of the issue provided (see below)

### Steps to Reproduce

1. Create a simple Grails app (using Grails 4.x) and add Spring Security Core plugin.
2. Configure Spring Security Core Plugin to use Digest Authentication according to the guide [here](https://grails-plugins.github.io/grails-spring-security-core/latest/#basicAndDigestAuth). The guide appears to be somewhat out of date regarding Digest because it mentions the call to `encodePassword` from the user class, but I did not find it there. I set the following three values in `application.groovy`:
```
grails.plugin.springsecurity.useDigestAuth
grails.plugin.springsecurity.digest.realmName
grails.plugin.springsecurity.digest.key
```
3. Attempt to run the application (did this via IntelliJ Idea).

### Expected Behaviour

The application should start.

Additionally, I think

### Actual Behaviour

Received the following stacktrace:
```
groovy.lang.MissingPropertyException: No such property: DigestAuthPasswordEncoder for class: grails.plugin.springsecurity.SpringSecurityCoreGrailsPlugin
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:65)
at org.codehaus.groovy.runtime.callsite.PogoGetPropertySite.getProperty(PogoGetPropertySite.java:51)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:309)
at grails.plugin.springsecurity.SpringSecurityCoreGrailsPlugin$_closure4.doCall(SpringSecurityCoreGrailsPlugin.groovy:829)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:101)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:323)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:263)
at groovy.lang.MetaClassImpl.invokePropertyOrMissing(MetaClassImpl.java:1276)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1219)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1041)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:821)
at grails.plugins.Plugin.invokeMethod(Plugin.groovy)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeOnDelegationObjects(ClosureMetaClass.java:397)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:337)
at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:64)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:51)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:156)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:168)
at grails.plugin.springsecurity.SpringSecurityCoreGrailsPlugin$_doWithSpring_closure12.doCall(SpringSecurityCoreGrailsPlugin.groovy:534)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:101)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:323)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:263)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1041)
at groovy.lang.Closure.call(Closure.java:405)
at groovy.lang.Closure.call(Closure.java:399)
at grails.spring.BeanBuilder.invokeBeanDefiningClosure(BeanBuilder.java:759)
at grails.spring.BeanBuilder.beans(BeanBuilder.java:588)
at grails.spring.BeanBuilder.invokeMethod(BeanBuilder.java:531)
at org.grails.plugins.DefaultGrailsPlugin.doWithRuntimeConfiguration(DefaultGrailsPlugin.java:543)
at org.grails.plugins.AbstractGrailsPluginManager.doRuntimeConfiguration(AbstractGrailsPluginManager.java:166)
at grails.boot.config.GrailsApplicationPostProcessor.postProcessBeanDefinitionRegistry(GrailsApplicationPostProcessor.groovy:171)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:125)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:705)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:531)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:312)
at grails.boot.GrailsApp.run(GrailsApp.groovy:96)
at grails.boot.GrailsApp.run(GrailsApp.groovy:456)
at grails.boot.GrailsApp.run(GrailsApp.groovy:443)
at com.mycompany.myproject.Application.main(Application.groovy:11)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
```

### Environment Information

- **Operating System**: Windows 10
- **GORM Version:** 7.0.4.RELEASE
- **Grails Version (if using Grails):** 4.0.3
- **JDK Version:** 1.8 (Amazon Corretto)

### Example Application

- TODO: link to Github repository with example that reproduces the issue

I do not have a link to an external repository. I think the steps to reproduce should suffice, but if absolutely necessary, I can generate a project and push it to github.

Start by reproducing the Grails 4.x application with Digest Authentication using the documented settings, then inspect SpringSecurityCoreGrailsPlugin.groovy around lines 829 and 534, where the stacktrace points. Done means the application starts with Digest Authentication enabled and the reported MissingPropertyException no longer occurs.

Written by the indexing model from the issue text.