LANG-1418 Clarify isAnyBlank(null) behavior in Javadoc.

[siddharthkarn2212]

This PR clarifies the Javadoc of StringUtils.isAnyBlank to explicitly describe
the behavior difference between a null CharSequence argument and a null array
of CharSequences.

No functional changes are made; this update aligns the documentation with
existing behavior and tests.

[garydgregory]

-1 Our documentation for this type of information is repeated in many places, over and over. It doesn't make sense to change one random sample. To me, this looks like change for the sake of change. The current documentation is brief and simple. IMO, this doesn't need to be more verbose. As it stands, I think this PR can be closed.

[siddharthkarn2212]

Thanks for the review, Gary.

I understand your point about avoiding redundant documentation and agree that the existing Javadoc is sufficient. I’m happy to close this PR.

Thanks for your time and feedback.