chore: act upon SonarQube warnings

[Mattias-Sehlstedt]

This further acts upon SonarQube warnings. The previous change brought down warnings from 50 to 31, this should reduce it quite a bit further.

Do note that it will most likely be necessary to at least mark this issue as "accepted/invalid", since the project is failing due to insufficient reliability rating

but the issues highlighted is not possible to fix since the suggested instanceOf cannot be applied out of the box since the class is package private.

[bnasslahsen]

Changes already applied into the main branch.
Thanks @Mattias-Sehlstedt for your PR!

[Mattias-Sehlstedt]

@bnasslahsen Do you happen to still have access to the SonarQube for the project? I would assume that the checks might pass now if this issue is marked as a false positive.

The common-lang bump also introduced a regression, where now the deprecated methods are used again (the Strings.CS is the underlying implementation of the methods, and those that are stated as the replacements). But this is very minor and I do not think it contributes to the analysis failure in SonarQube.

[bnasslahsen]

@Mattias-Sehlstedt,

Yes i have access to it: https://sonarcloud.io/project/issues?impactSeverities=HIGH&issueStatuses=OPEN%2CCONFIRMED&branch=main&id=springdoc_springdoc-openapi

I will work on it to get it fixed

[Mattias-Sehlstedt]

🚀