Enforce empty or useless constructor comments can't be used

[sgiehl]

Description

Enables PHPCS rules

• SlevomatCodingStandard.Commenting.EmptyComment
• SlevomatCodingStandard.Commenting.ForbiddenComments
  Restricted to disallow Constructor. comments

Note: PHPCS currently replaces those Constructor. comments with an empty line. This might cause multiple empty comment lines, which isn't nice as well. But we can use a different rule to enforce proper spacing in comments later.

Checklist

• [NA] I have understood, reviewed, and tested all AI outputs before use
• [NA] All AI instructions respect security, IP, and privacy rules

Review

• Functional review done
• Potential edge cases thought about (behaviour of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• New documentation added or existing documentation updated