feat(ocp): expose whether talk is enabled for user

[hamza221]

Summary

Expose the Talk app admin settings start_conversations and allowed_groups through OCP

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI (Tests were AI generated)

[nickvergessen]

Suggested change

	* Check if Talk is disabled for the logged in user, respecting the
	* per-group restriction configured in Talk admin settings
	* (start_conversations).
	*
	* Check if Talk is disabled for the logged in user.
	*

The idea of the abstraction in OCP is to not reference Talk details iirc.
So should also not reference internal app configs 🙈

[nickvergessen]

Also, while I know the config in Talk is like this. I would name it positively, so have a isEnabledForUser

[nickvergessen]

Should be the same here positive phrase and method name:

Suggested change

	* Check if the logged in user is not allowed to create conversations,
	* respecting the per-group restrictions configured in Talk admin settings
	* (allowed_groups).
	*
	* Returns false when Talk is not available at all.
	* Check if the logged in user is allowed to create conversations.

But while this is "trivial" at the moment, we have a pending request to allow "internal" conversations but block "public" conversations.
The question is whether we add a bool for public or the IConversationOptions as a parameter here.

But I guess from your calendar PR you don't know what kind of conversation the user is going to create? So maybe we keep it this way, and Talk returns true if a user is allowed to create any conversation here.
But creation call itself might still fail?