Adds tooltip for compose menu

[byteplow]

Adds tooltip New conversation to Compose Menu Button In Room List Header.

Checklist

• I have read through review guidelines and CONTRIBUTING.md.
• Tests written for new code (and old code if feasible).
• New or updated public/exported symbols have accurate TSDoc documentation.
• Linter and other CI checks pass.
• I have licensed the changes to Element by completing the Contributor License Agreement (CLA)

[t3chguy]

I believe the aria-label is overwritten by the label of the parent Tooltip, causing your tests to fail. I believe this uses Add because the menu also lets you create rooms so Start chat would be a misleading tooltip for that

Also there should probably be a tooltip consistently between the Start chat single-button variant of this button and the menu-trigger "Add" variant

[byteplow]

I chose 'Start chat' because 'Add' did not seem clear to me. ("Add what?") I assumed that a room was also a chat (group chat). I see that this is misleading in terms of the element naming convention. Especially if the button also allows to create a video room. Would 'Add room' fit the element naming convention? A chat is also a room. I guess our users could understand that. Otherwise, I will try to come up with a better tooltip or just use 'Add'.

[t3chguy]

Would 'Add room' fit the element naming convention?

It'd fit within the Matrix naming convention but I think Design would not be happy as they definitely do not want DMs to be seen as rooms, so that would definitely need design sign-off which can take a while to get.

[byteplow]

New conversation? "Conversation" is alrady being used in some places for room and dms. e.g:

• "Start a conversation with someone using their name or username (like <userId/>)."
• "Recent Conversations"
• "Own your conversations."

[florianduros]

@byteplow the PR has lint errors, you can run yarn lint to list them.