Programming exercises: Upgrade deprecated PMD rules

[Strohgelaender]

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.
• This is a small issue that I tested locally and was confirmed by another developer on a test server.
• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

Motivation and Context

The default PMD configuration contains some deprecated PMD rules that got removed in PMD 7.

Description

This PR prepares for the PMD 7 upgrade by repacing the rules with their successor.

Steps for Testing

Create a new Java programming exercise with SCA enabled.

Check the build logs and verify that no more ruleset deprecation warnings are present.

Testserver States

Note

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Green = Currently available, Red = Currently locked

Review Progress

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Summary by CodeRabbit

• Chores
  • Updated the PMD tool version to 6.55.0 for improved code analysis.

[JohannesWt]

Small changes look good

[rstief]

Code