Fix: Resolve duplicate webClientBuilder and restClientBuilder beans

[casc84ab]

Summary

• Rename webClientBuilder() to fireflyServiceWebClientBuilder() with explicit @ConditionalOnMissingBean(WebClient.Builder.class) to prevent conflict with WebClientConfig in fireflyframework-core
• Rename restClientBuilder() to fireflyRestClientBuilder() with @ConditionalOnMissingBean(RestClientBuilder.class) to prevent conflict with Spring Boot's RestClientAutoConfiguration

Test plan

• All 405 fireflyframework-client tests pass
• All 36 microservice repos compile and pass tests
• 29/36 microservices start cleanly with zero duplicate bean warnings

[ancongui]

LGTM. Two improvements here:

1. Explicit @ConditionalOnMissingBean type: Changing from bare @ConditionalOnMissingBean (which infers type from factory method return type) to explicit @ConditionalOnMissingBean(WebClient.Builder.class) / @ConditionalOnMissingBean(RestClientBuilder.class) makes the intent clear and avoids subtle inference issues.

2. Bean method renames: webClientBuilder → fireflyServiceWebClientBuilder and restClientBuilder → fireflyRestClientBuilder disambiguates from Spring Boot's own beans. Note this changes bean names, but since injection is typically by type (and the conditional checks by type), this is safe. Test plan confirms all 405 tests + 36 microservices pass.