Create a “global” enable/disable option for disabling metrics/tracing in tests

[asibross]

The introduction of ObservabilityContextCustomizerFactory and @AutoConfigureObservability is breaking smoke/integration tests that were relying on certain beans to exists. Basically any auto-configuration that uses @ConditionalOnEnabledTracing when creating beans will be missed in the test context. The purpose of this issue is to request that this disabling metric/tracing functionality be controlled by a property.

CC: @jonatan-ivanov