* INT-4550: Disallow multi aggregators on same MGS
JIRA: https://jira.spring.io/browse/INT-4550
**Cherry-pick to 5.0.x**
* * Introduce `UniqueExpiryCallback`
* Use `UniqueExpiryCallback` in the `AbstractCorrelatingMessageHandler`
* Check for uniqueness in the `AbstractMessageGroupStore`
* Remove duplicate code in the `ConfigurableMongoDbMessageStore`
* * Fix tests according a new logic
* * Address PR review
* Change `Assert.isTrue` to the `logger.error` for backward compatibility
* Revert changes in tests since we don't throw exception anymore
* Fix language on doc
* * Fix Checkstyle violation in the `AbstractMessageGroupStore`
* * Ignore `testDontReapMessageOfOtherHandler()`
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