introduce private method to remove duplicated codes

[aaaZayne]

Refactor parameter retrieval methods in Parameters class to remove clones.

Checklist

• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Make sure gitHub actions can pass. Why the workflow is failing and how to fix it?

[zrlw]

LGTM

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.78%. Comparing base (d95086c) to head (a887760).
⚠️ Report is 31 commits behind head on 3.3.

Files with missing lines	Patch %	Lines
.../main/java/org/apache/dubbo/common/Parameters.java	0.00%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                3.3   #16218      +/-   ##
============================================
- Coverage     60.79%   60.78%   -0.01%     
- Complexity    11751    11758       +7     
============================================
  Files          1953     1953              
  Lines         89119    89110       -9     
  Branches      13444    13440       -4     
============================================
- Hits          54179    54166      -13     
- Misses        29369    29371       +2     
- Partials       5571     5573       +2     

Flag	Coverage Δ
integration-tests-java21	32.17% <0.00%> (-0.01%)	⬇️
integration-tests-java8	32.23% <0.00%> (+0.03%)	⬆️
samples-tests-java21	32.16% <0.00%> (+0.04%)	⬆️
samples-tests-java8	29.85% <0.00%> (-0.01%)	⬇️
unit-tests-java11	59.02% <0.00%> (-0.01%)	⬇️
unit-tests-java17	58.54% <0.00%> (+<0.01%)	⬆️
unit-tests-java21	58.54% <0.00%> (+0.02%)	⬆️
unit-tests-java25	58.50% <0.00%> (+0.02%)	⬆️
unit-tests-java8	59.05% <0.00%> (-0.01%)	⬇️

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