Add unit test for ConsumerContextClusterInterceptor

[icankeep]

What is the purpose of the change

issue: #7971
Add unit test for ConsumerContextClusterInterceptor

Brief changelog

Verifying this change

Checklist

• Make sure there is a GitHub_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GitHub issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
• Each commit in the pull request should have a meaningful subject line and body.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Check if is necessary to patch to Dubbo 3 if you are work on Dubbo 2.7
• Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Add some description to dubbo-website project if you are requesting to add a feature.
• GitHub Actions works fine on your own branch.
• If this contribution is large, please follow the Software Donation Guide.

[codecov-commenter]

Codecov Report

Merging #7972 (79388c1) into master (3894047) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #7972      +/-   ##
============================================
- Coverage     60.87%   60.85%   -0.03%     
  Complexity      490      490              
============================================
  Files          1089     1089              
  Lines         43876    43876              
  Branches       6413     6413              
============================================
- Hits          26710    26699      -11     
- Misses        14197    14209      +12     
+ Partials       2969     2968       -1     

Impacted Files	Coverage Δ
...interceptor/ConsumerContextClusterInterceptor.java	90.00% <ø> (+10.00%)	⬆️
...che/dubbo/remoting/transport/mina/MinaChannel.java	35.52% <0.00%> (-10.53%)	⬇️
...dubbo/remoting/exchange/support/DefaultFuture.java	82.05% <0.00%> (-9.41%)	⬇️
.../apache/dubbo/remoting/transport/AbstractPeer.java	58.69% <0.00%> (-4.35%)	⬇️
...pache/dubbo/registry/support/AbstractRegistry.java	77.40% <0.00%> (-2.60%)	⬇️
...etadata/report/support/AbstractMetadataReport.java	59.70% <0.00%> (-0.98%)	⬇️
...rg/apache/dubbo/common/timer/HashedWheelTimer.java	79.72% <0.00%> (-0.69%)	⬇️
...org/apache/dubbo/registry/redis/RedisRegistry.java	48.61% <0.00%> (-0.40%)	⬇️
...apache/dubbo/common/extension/ExtensionLoader.java	81.49% <0.00%> (+0.22%)	⬆️
...he/dubbo/registry/multicast/MulticastRegistry.java	70.23% <0.00%> (+0.93%)	⬆️
... and 7 more

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[xiaoheng1]

LGTM