Recompute message cache for auto translation.

[vickyokrm]

Description:

The messages on UI are cached. This prevents the re-computation of auto translated messages. Therefore, when the re-render of translated message happens the original message has to be replaced by the translated message.

Reason: The key for each cached message is msg._id + _updated.id. So the translated message with same key exists already in the cache and therefore the translated message will be ignored.

Steps to reproduce:

1. Subscribe to a channel and activated the auto translate feature to your wish language.
2. Ask someone to write a message to the channel in a different language then you have configured.
3. The translated message will not replace the original message. Although the message has been translated which can be seen in the database.

Expected behavior:

The original message has to be replaced with the translated message.

Actual behavior:

This behaviour is intermittent. Sometimes the original message is not replaced by the translated message.