Some uses of hard-coded ChatMessage class ignore configured documentClass

[Fyorl]

Originally reported by Cousken#7485 https://discord.com/channels/170995199584108546/956307084931112960/1067085540509368360

I think i found a code bug, unsure how to report it.

tooltip: ChatMessage.metadata.labelPlural,

In sidebar.js, getData function row 65 and onwards.

Hardcoded classes are used for getting tooltips for tabs. If i create a new class that extends ChatMessage with it's own metadata and set it up as a message document class, i expect it to affect the tooltips, which it currently doesn't.

[Fyorl]

We have fixed some instances where ChatMessage.create was being used instead of ChatMessage.implementation.create, however, in regards to the issue reported in the body, replacing any Document metadata is not supported. For changing labels, the system should override the localisation key rather than attempting to change metadata.labelPlural.