feat: spring boot 4 support secretmanager

[mehdi0933]

Description

This PR addresses the need for Spring Boot 4.0 compatibility within the Secret Manager module and adds a security feature for data sanitization in Actuator endpoints.

Changes

• Sanitization: Added SecretManagerSanitizingFunction to mask values starting with sm:// in Actuator endpoints, preventing sensitive reference leaks.
• Spring Boot 4.0 Support:
  • Moved autoconfiguration registration from spring.factories to the new modular structure: META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports.
  • Updated directory structure to comply with Spring Boot 3.x/4.x best practices.

Fixes #4183

[bushwakko]

This doesn't seem like the right content for the imports file?

[mehdi0933]

Hi @bushwakko, thanks for the catch! You're right. I might have kept the old spring.factories format by mistake. I will update the .imports file to ensure it only contains the fully qualified class names, one per line, as required by the new Spring Boot autoconfiguration registration. I'll push a fix shortly.

[mehdi0933]

Hi @bushwakko, I have updated the autoconfiguration imports to use the correct format (FQN, one per line) and removed the old spring.factories content.

I also took the opportunity to:

Fix all Checkstyle violations using google-java-format.

Refactor Spanner lifecycle events to use wildcard generics (Iterable<?>) for full Spring Framework 7 compatibility.

All local validations are passing. Ready for your review!