fix(native): Resolve NullPointerException in ReferenceBeanManager

[kyounghunJang]

What is the purpose of the change?

This commit adds a defensive null-check for moduleModel. If it is null, it retrieves the model explicitly using DubboBeanUtils.getModuleModel() to prevent the NullPointerException and ensure stable initialization in native builds.

fixes: #15663

Checklist

• Make sure there is a GitHub_issue field for the change.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test to verify your logic correction. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Make sure gitHub actions can pass. Why the workflow is failing and how to fix it?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 61.07%. Comparing base (dea0206) to head (3a5d795).

Files with missing lines	Patch %	Lines
.../config/spring/reference/ReferenceBeanManager.java	0.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##                3.3   #15721   +/-   ##
=========================================
  Coverage     61.06%   61.07%           
- Complexity    11700    11709    +9     
=========================================
  Files          1924     1924           
  Lines         87086    87088    +2     
  Branches      13115    13116    +1     
=========================================
+ Hits          53182    53186    +4     
  Misses        28460    28460           
+ Partials       5444     5442    -2     

Flag	Coverage Δ
integration-tests-java21	32.83% <0.00%> (-0.02%)	⬇️
integration-tests-java8	33.09% <0.00%> (+0.14%)	⬆️
samples-tests-java21	32.66% <0.00%> (+0.08%)	⬆️
samples-tests-java8	30.35% <0.00%> (+0.01%)	⬆️
unit-tests-java11	59.03% <0.00%> (+<0.01%)	⬆️
unit-tests-java17	58.76% <0.00%> (-0.01%)	⬇️
unit-tests-java21	58.79% <0.00%> (-0.01%)	⬇️
unit-tests-java8	59.03% <0.00%> (-0.01%)	⬇️

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[Copilot]

Pull Request Overview

Adds a defensive null-check and fallback retrieval of moduleModel in ReferenceBeanManager.initReferenceBean to prevent NullPointerException during native builds.

• Adds a null-check for moduleModel and falls back to DubboBeanUtils.getModuleModel(applicationContext)
• Continues with reference registration using the resolved moduleModel

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[zrlw]

It is inappropriate to check moduleModel at here, and you should not use force-push before you know what you do.

[zrlw]

lazy getting moduleModel at prepareReferenceBeans might be better.
#15663 (comment)