Allow access to context locals from `HttpServerMetricsTagsContributor`

[adutra]

Description

Right now when HttpServerMetricsTagsContributor.contribute() is invoked the request context is not active anymore. This limits the ability to pass any request-specific information to the contributor.

Implementation ideas

No response

[quarkus-bot]

/cc @ebullient (metrics), @jmartisk (metrics)