NIFI-16368 Improve validation for Parameter Context ID values

[exceptionfactory]

Summary

NIFI-16368 Improves input validation for Parameter Context identifiers provided through URL and request entity fields in REST Resource methods.

Changes include a new shared private method for identifier validation and comparison, along with unit test updates to verify expected validation behavior.

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  • JDK 21
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[pvillard31]

Should submitParameterContextUpdate also use this helper so all three endpoints apply the same validation and error messages?

[exceptionfactory]

Thanks @pvillard31, although that method was already checking the values, I agree it makes sense to reuse the new method.

[pvillard31]

LGTM, will merge once the checks are green