fix: do not report disabled instrumentations as failures

[0robustus1]

It can be very confusing to see a Instrumentation: OpenTelemetry::Instrumentation::Sinatra failed to install log line when that instrumentation is in fact just disabled (via enabled: false) or OTEL_RUBY_INSTRUMENTATION_SINATRA_ENABLED=false. This instead reports it as a not-enabled instrumentation.

[xuan-cao-swi]

Thanks for bringing this up. Since you're already working on this, could you also include a compatibility check (e.g., Instrumentation: #{instrumentation.name} failed to install: compatibility issue)?

[0robustus1]

@xuan-cao-swi good point. Added it.

[0robustus1]

Test failure seems to report on other PRs as well:

1) Failure:
OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor::dropped spans metrics#test_0001_reports consistent label keys [test/opentelemetry/sdk/trace/export/batch_span_processor_test.rb:407]:
Expected: nil
  Actual: ["code.function", "reason"]

So it might be broken on main?