Fixes: #9103
The `IntegrationRequestMappingHandlerMapping` implements a `DestructionAwareBeanPostProcessor`
which causes an early bean initialization including interceptors loading from the application context:
```
2024-04-26 12:11:07,434 WARN [main] [org.springframework.context.support.PostProcessorRegistrationDelegate$BeanPostProcessorChecker] - Bean '(inner bean)#39f5b723' of type [org.springframework.web.servlet.handler.ConversionServiceExposingInterceptor] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying). Is this bean getting eagerly injected into a currently created BeanPostProcessor [integrationRequestMappingHandlerMapping]? Check the corresponding BeanPostProcessor declaration and its dependencies.
```
* Extract the `DestructionAwareBeanPostProcessor` logic from the `IntegrationRequestMappingHandlerMapping`
into separate `DynamicRequestMappingBeanPostProcessor` which does not cause eager beans initialization
* Verify with the `IntegrationGraphControllerTests` that the mentioned `not eligible for auto-proxying` warning is not emitted anymore
**Auto-cherry-pick to `6.2.x`**
5d592713c4