Fixes: #9430
When `CachingClientConnectionFactory` is used in combination of
`Tcp.outboundAdapter()` & `Tcp.inboundAdapter()`, the connection is not released
back to the cache because `CachingClientConnectionFactory` does not store
created connections into its `connections` property.
So, when `TcpReceivingChannelAdapter` calls `this.clientConnectionFactory.closeConnection(connectionId);`
it returned immediately because there is nothing to remove from the `this.connections`
* Add `protected removeConnection()` in the `AbstractConnectionFactory`
and override it in the `CachingClientConnectionFactory` with delegation to the `this.targetConnectionFactory`
* Demonstrate the problem in the new `IpIntegrationTests.allRepliesAreReceivedViaLimitedCachingConnectionFactory()` test
and ensure that all 27 letters from English alphabet are sent to the server and received in uppercase
while size of the `CachingClientConnectionFactory` is only `10`
**Auto-cherry-pick to `6.3.x` & `6.2.x`**
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