[3.3] Bump io.micrometer:micrometer-tracing-bom from 1.5.1 to 1.6.0 and rewrite DubboMicrometerTracingAutoConfigurationTests for jdk8 compatibility

[zrlw]

What is the purpose of the change?

1. https://github.com/apache/dubbo/pull/15818 tested failed, the root cause is the new version classes Tracer and Propagator could not be mocked by mockito 4.x
2. mockito 5 doesn't support jdk8 but dubbo still needs to support, so we could not bump mockito to 5 by now

Checklist

• [x] Make sure there is a GitHub_issue field for the change.
• [x] Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• [x] Write necessary unit-test to verify your logic correction. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• [x] Make sure gitHub actions can pass. Why the workflow is failing and how to fix it?

[codecov-commenter]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 60.77%. Comparing base (9fffe62) to head (d626e8a).

Additional details and impacted files

@@             Coverage Diff              @@
##                3.3   #15838      +/-   ##
============================================
- Coverage     60.78%   60.77%   -0.02%     
+ Complexity    11712    11702      -10     
============================================
  Files          1938     1938              
  Lines         88692    88692              
  Branches      13387    13387              
============================================
- Hits          53915    53903      -12     
- Misses        29256    29257       +1     
- Partials       5521     5532      +11     

Flag	Coverage Δ
integration-tests-java21	32.36% <ø> (ø)
integration-tests-java8	32.44% <ø> (-0.01%)	:arrow_down:
samples-tests-java21	32.04% <ø> (-0.03%)	:arrow_down:
samples-tests-java8	29.73% <ø> (+0.01%)	:arrow_up:
unit-tests-java11	59.09% <ø> (+0.02%)	:arrow_up:
unit-tests-java17	58.58% <ø> (-0.01%)	:arrow_down:
unit-tests-java21	58.57% <ø> (+0.01%)	:arrow_up:
unit-tests-java25	58.52% <ø> (-0.02%)	:arrow_down:
unit-tests-java8	59.09% <ø> (+0.02%)	:arrow_up:

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