[Task] Add support for setting and reading `m.status` and `m.call` profile fields via MSC4426

[pixlwave]

MSC4426 defines m.status and m.call fields on the user profile. We should add support for getting and setting these fields and include them in the various user profile types found throughout the SDK. Specifically at the FFI layer:

• RoomMemberDetails (to show in the room member list)
• ProfileDetails (to show in the timeline)
• The main SDK's Account for showing ownUser's status.

Ruma already supports custom user profile fields but does not yet contain the structs for these 2 specific fields.

[pixlwave]

PR for Ruma is here: ruma/ruma#2498 🤞

[pixlwave]

The Ruma PR above is merged, the next steps as I see it are:

• Expose methods to set the user's own m.status right up to the FFI (in theory m.call will be handled by Element Call so from an Element X perspective we don't need to worry about this).
• Add support for storing profiles synced via SSS (#6617)
• Add status and call fields to RoomMemberDetails and ProfileDetails and fill in the values from the stored profiles.
• We should probably combine Client::avatar_url and Client::display_name into a Client::own_profile that returns a ProfileDetails with all of the supported fields (presumably filled in by the stored profiles from SSS, assuming our own profile is included in the sync – see MSC4262: Sliding Sync Extension: Profile Updates matrix-spec-proposals#4262 (comment))

[pixlwave]

Handled by

• MSC4426 : support set/clear/fetch own user status  #6703
• Profiles: Add status and call fields to RoomMember and the UI crate's Profile. #6704
• Profiles: Allow building a sync service with support for the profiles extension. #6726
• Profiles: Add status and call fields to room heroes. #6733
• Profiles: Add a method to subscribe to the user's own profile. #6760

Not yet tested against a server so 🤞