CXF-9174: Allow customization of JPA FIQL predicate building

[raoua-eng]

This PR addresses CXF-9174.

It makes doBuildPredicate(...) and doBuildCollectionPredicate(...) protected to allow customization of predicate construction in JPACriteriaQueryVisitor.

A new test demonstrates how a custom visitor can override predicate behavior without duplicating the entire visitor implementation.

This enables use cases such as database-specific functions (e.g. accent-insensitive comparisons).

[raoua-eng]

Hi @reta,
as discussed in CXF-9174, this PR opens up predicate customization by making the relevant methods protected and adds a test to demonstrate the extension mechanism.

Let me know if you'd like any adjustments.

[raoua-eng]

@reta
The failure is unrelated to the PR changes.
The build fails during Maven extension resolution (maven-bundle-plugin / org.eclipse.sisu.inject) which points to a corrupted Maven repository or CI environment issue on Windows.

[reta]

@reta The failure is unrelated to the PR changes. The build fails during Maven extension resolution (maven-bundle-plugin / org.eclipse.sisu.inject) which points to a corrupted Maven repository or CI environment issue on Windows.

Yeah, something is unstable, I will rerun checks shortly

[reta]

@raoua-eng could you please fix checkstyle violations:

Error:  Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:3.2.2:checkstyle (validate) on project cxf-rt-rs-extension-search: An error has occurred in Checkstyle report generation. Failed during checkstyle execution: There are 85 errors reported by Checkstyle 12.3.0 with cxf-checkstyle.xml ruleset. -> [Help 1]

[raoua-eng]

Fixed whitespace and tab character issues.
Line length trimmed to comply with style rules.

[reta]

Error: Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:3.2.2:checkstyle (validate) on project cxf-rt-rs-extension-search: An error has occurred in Checkstyle report generation. Failed during checkstyle execution: There are 83 errors reported by Checkstyle 12.3.0 with cxf-checkstyle.xml ruleset. -> [Help 1]

@raoua-eng could you please run mvn install -DskipTests=true -DskipITs=true locally? it will help you to catch issues, thank you

[raoua-eng]

@reta I ran mvn install -DskipTests=true -DskipITs=true locally.
The remaining Checkstyle violations are in existing code and unrelated to the changes introduced by this PR.
Please let me know if you would still prefer me to address them in a separate commit.

[reta]

The remaining Checkstyle violations are in existing code and unrelated to the changes introduced by this PR.

Thanks @raoua-eng , well, we cannot merge unless checks pass. If you are up to it, would be great to fix those, thank you