Fixes https://github.com/spring-projects/spring-integration/issues/8692 * Added `createIndexes` in `AbstractConfigurableMongoDbMessageStore` * Added Javadoc for `setCreateIndex()` method * Removed `afterPropertiesSet()` in `MongoDbChannelMessageStore` and update `whats-new.adoc` and `mongodb.adoc` files **Cherry-pick to `6.1.x` & `6.0.x`**