Remove Spring SDK MetricsRegistry workarounds in tests

[megglos]

Description

The Spring SDK offers an automatic actuator metrics setup in case actuator and MetricMeter classes are present via CamundaActuatorConfiguration.

However it turned out that the SDK was always setting up the MicrometerMetricsRecorder accidentally by default as optional dependencies containing those classes were not flagged as optional in the SDK. This changed with camunda/camunda#31991 .

In the meantime this lead to two different workarounds within ZPT:

• on main a MetricsRegistry bean was added to the test setup, while actually not needed for testing
• on stable/8.6 & stable/8.7 one of the transitive dependencies that trigger this behavior was excluded

Once camunda/camunda#31991 is merged and backported and released, we can remove these workarounds as the Spring SDK will then properly provide a default NoopMetricsRecorder which is suffice for test setups.