Can't create a WebService class via Assistant in a Gradle project

### Apache NetBeans version

Apache NetBeans 14, 15

### What happened

I have created a new Gradle web application.
Then I have tried to create a new web service class.
I tried to finalize the process.
This ended in the following exception:
```
java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "creator" is null
at org.netbeans.modules.websvc.core.dev.wizard.NewWebServiceWizardIterator.instantiate(NewWebServiceWizardIterator.java:78)
at org.openide.loaders.TemplateWizard.handleInstantiate(TemplateWizard.java:602)
at org.openide.loaders.TemplateWizard.instantiateNewObjects(TemplateWizard.java:436)
at org.openide.loaders.TemplateWizardIterImpl.instantiate(TemplateWizardIterImpl.java:223)
at org.openide.loaders.TemplateWizardIteratorWrapper.instantiate(TemplateWizardIteratorWrapper.java:135)
at org.openide.WizardDescriptor.callInstantiateOpen(WizardDescriptor.java:1605)
at org.openide.WizardDescriptor.callInstantiate(WizardDescriptor.java:1546)
at org.openide.WizardDescriptor.access$2300(WizardDescriptor.java:67)
[catch] at org.openide.WizardDescriptor$Listener$2$1.run(WizardDescriptor.java:2233)
at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1418)
at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:45)
at org.openide.util.lookup.Lookups.executeWith(Lookups.java:278)
at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)
```
which was shown in the "Notifications" panel.

### How to reproduce

The steps to reproduce are shown in the "What happened" section. This happened since version 12 of Netbeans.

### Did this work correctly in an earlier version?

No

### Operating System

Windows 11 21H1 22000.739
Windows 10.0.19044

### JDK

Azul Systems zulu18.30.11-ca-fx-jdk18.0.1 win_x64
Azul Systems Zulu18.32+11-CA (build 18.0.2+9) win_x64

### Apache NetBeans packaging

Apache NetBeans binary zip

### Anything else

_No response_

### Are you willing to submit a pull request?

Yes

### Code of Conduct

Yes

Start in org.netbeans.modules.websvc.core.dev.wizard.NewWebServiceWizardIterator.instantiate, identified by the stack trace, and reproduce the failure by creating a Gradle web application and using the New Web Service Class wizard. Trace why the creator is null and verify that the wizard completes without the NullPointerException and creates the requested web service class.

Written by the indexing model from the issue text.