refactor: optimize ExtensionLoader code style

[linjianming02]

What is the purpose of the change

Brief changelog

Verifying this change

Checklist

• [x] 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.
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• [ ] Check if is necessary to patch to Dubbo 3 if you are work on Dubbo 2.7
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[codecov-commenter]

Codecov Report

Merging #10229 (6988dcd) into master (f1ca2b4) will decrease coverage by 0.00%. The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master   #10229      +/-   ##
============================================
- Coverage     60.93%   60.93%   -0.01%     
- Complexity      446      449       +3     
============================================
  Files          1100     1100              
  Lines         44582    44495      -87     
  Branches       6494     6483      -11     
============================================
- Hits          27167    27113      -54     
+ Misses        14446    14418      -28     
+ Partials       2969     2964       -5     

Impacted Files	Coverage Δ
...apache/dubbo/common/extension/ExtensionLoader.java	79.52% <100.00%> (-0.69%)	:arrow_down:
...ng/transport/dispatcher/all/AllChannelHandler.java	82.75% <0.00%> (-13.80%)	:arrow_down:
.../exchange/support/header/HeaderExchangeServer.java	67.61% <0.00%> (-2.86%)	:arrow_down:
...common/serialize/hessian2/Hessian2ObjectInput.java	90.47% <0.00%> (-1.53%)	:arrow_down:
...ommon/serialize/hessian2/Hessian2ObjectOutput.java	93.93% <0.00%> (-0.66%)	:arrow_down:
...rg/apache/dubbo/common/timer/HashedWheelTimer.java	80.20% <0.00%> (+0.48%)	:arrow_up:
...ting/zookeeper/curator/CuratorZookeeperClient.java	69.51% <0.00%> (+1.06%)	:arrow_up:
...pache/dubbo/registry/support/AbstractRegistry.java	80.74% <0.00%> (+1.11%)	:arrow_up:
.../src/main/java/org/apache/dubbo/rpc/RpcStatus.java	73.80% <0.00%> (+1.19%)	:arrow_up:
... and 3 more

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