fix:the Configuration Cluster and retries

[redoom]

Problem

Previously, Dubbo's cluster fault-tolerance strategy could only be configured on the consumer side via @DubboReference(cluster = "..."). Provider-side configuration via @DubboService(cluster = "...") was ignored.

Solution

Modified RegistryProtocol to support provider-side cluster configuration with consumer-side override capability:

• Check if consumer has explicitly configured cluster parameter
• If not, fetch cluster configuration from provider's URL metadata
• Consumer config takes precedence over provider config

Usage Example

Provider side

@DubboService(cluster = "failsafe")
public class GreetingServiceImpl implements GreetingService {
    @Override
    public String sayHello(String name) {
        return "Hello " + name;
    }
}

Consumer side (will use provider's failsafe strategy)

@DubboReference
private GreetingService greetingService;

Consumer override (explicit config takes precedence)

@DubboReference(cluster = "failover")
private GreetingService greetingService;

Priority Order

1. Consumer-side explicit configuration (highest priority)
2. Provider-side configuration (fallback)
3. Default strategy: failover

Related Issues

#15668

[codecov-commenter]

Codecov Report

❌ Patch coverage is 69.23077% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.77%. Comparing base (7b48706) to head (f1047d6).
⚠️ Report is 3 commits behind head on 3.3.

Files with missing lines	Patch %	Lines
...e/dubbo/registry/integration/RegistryProtocol.java	69.23%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                3.3   #15821      +/-   ##
============================================
+ Coverage     60.75%   60.77%   +0.02%     
- Complexity    11695    11704       +9     
============================================
  Files          1938     1938              
  Lines         88679    88692      +13     
  Branches      13386    13391       +5     
============================================
+ Hits          53877    53904      +27     
+ Misses        29270    29256      -14     
  Partials       5532     5532              

Flag	Coverage Δ
integration-tests-java21	32.44% <61.53%> (+0.07%)	⬆️
integration-tests-java8	32.45% <61.53%> (+<0.01%)	⬆️
samples-tests-java21	32.04% <69.23%> (-0.03%)	⬇️
samples-tests-java8	29.69% <69.23%> (+0.04%)	⬆️
unit-tests-java11	59.06% <61.53%> (+<0.01%)	⬆️
unit-tests-java17	58.53% <61.53%> (+<0.01%)	⬆️
unit-tests-java21	58.56% <61.53%> (-0.01%)	⬇️
unit-tests-java25	58.51% <61.53%> (-0.01%)	⬇️
unit-tests-java8	59.06% <61.53%> (+0.01%)	⬆️

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[zrlw]

it might be better to add new test cases for this PR.