Ensure grouping a dimension in ms doesn't fail if ranking query limit is reached

[sgiehl]

Description:

When grouping dimension values it might happen that a ranking query already limited the amount of records. In that case a row with value __mtm_ranking_query_others__ will occur.

This currently fails for dimensions in milliseconds, as calculating with the __mtm_ranking_query_others__ value doesn't work.

This PR ensures that only numeric values are taken into account for that calculation.

fixes #22579

(Ref DEV-18521)

Review

• Functional review done
• Potential edge cases thought about (behavior 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
• Documentation added if needed
• Existing documentation updated if needed

[michalkleiner]

The change looks safe.

It seems there are no tests around this, however we think the tests should be added within the CustomReports plugin to test with lower ranking limits.