Active job handlers no longer honour configuration changes

[lavoiesl]

          This is causing a regression in our codebase because the handler no longer honours dynamic configuration.

i.e. Changing OpenTelemetry::Instrumentation::ActiveJob::Instrumentation.instance after this is registered no longer affects the naming.

Arguably, we probably shouldn't rely on dynamic configs, but I wanted to point it out regardless

Same applies to Perform

Originally posted by @lavoiesl in #677 (comment)