Remove needless toString convert For 2.6

[AlbumenJ]

What is the purpose of the change

Brief changelog

Verifying this change

• 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.
• Format the pull request title like [Dubbo-XXX] Fix UnknownException when host config not exist #XXX. 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.
• 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.
• Run mvn clean install -DskipTests=false & mvn clean test-compile failsafe:integration-test to make sure unit-test and integration-test pass.
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[codecov-commenter]

Codecov Report

Merging #8093 (89bf025) into 2.6.x (fc1bdfa) will increase coverage by 0.01%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##              2.6.x    #8093      +/-   ##
============================================
+ Coverage     47.07%   47.08%   +0.01%     
- Complexity     4466     4472       +6     
============================================
  Files           573      573              
  Lines         25595    25596       +1     
  Branches       4541     4541              
============================================
+ Hits          12049    12053       +4     
- Misses        11689    11692       +3     
+ Partials       1857     1851       -6     

Impacted Files	Coverage Δ
...java/com/alibaba/dubbo/common/utils/PojoUtils.java	49.56% <0.00%> (-0.15%)	⬇️
...onfig/spring/extension/SpringExtensionFactory.java	66.66% <0.00%> (-16.67%)	⬇️
.../rpc/protocol/dubbo/LazyConnectExchangeClient.java	57.31% <0.00%> (-4.88%)	⬇️
...ba/dubbo/remoting/transport/netty/NettyServer.java	68.42% <0.00%> (-3.51%)	⬇️
...baba/dubbo/remoting/transport/mina/MinaClient.java	56.92% <0.00%> (-1.54%)	⬇️
...libaba/dubbo/rpc/protocol/dubbo/DubboProtocol.java	60.08% <0.00%> (+1.75%)	⬆️
...rc/main/java/com/alibaba/dubbo/rpc/RpcContext.java	33.33% <0.00%> (+3.47%)	⬆️
...om/alibaba/dubbo/rpc/filter/ActiveLimitFilter.java	83.33% <0.00%> (+5.55%)	⬆️
...ubbo/common/compiler/support/AdaptiveCompiler.java	88.88% <0.00%> (+11.11%)	⬆️
...bo/rpc/cluster/support/FailbackClusterInvoker.java	86.84% <0.00%> (+13.15%)	⬆️

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