[processor/filterprocessor] enable expr evaluation on non-string type metric labels

[boostchicken]

Description: Allows use of more datatypes than string in matcher

Link to tracking Issue: #12479

Testing: Existing unit tests

Documentation: Updated filterprocessor docs

[boostchicken]

Note this is a breaking change, could make it non breaking by always returning a string representation as suggested in issue, I prefer this way

[github-actions[bot]]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[github-actions[bot]]

Closed as inactive. Feel free to reopen if this PR is still being worked on.