…platform on top

…orm when more were enabled

…form when restoring settings

Remove comments about handling custom destinations and primary platform
not supporting chat, in the worst case we should be handling this either
on the `LiveDock` or perhaps on the service (if they're not supported as
of now).

Auto-select primary platform even if the user has multiple platforms as
part of onboarding, since it was requested now that the user would be
able to disable/enable primary platform from their Go Live window.
This should soft-skip the primary platform select step as part of
Onboarding by applying the same logic than before where they had a
single platform linked to their Streamlabs ID.

With Tiktok being part of the active platforms seemingly at all times,
will make `PrimaryChatSwitcher` blow up since it doesn't technically
support chat. We have refactored to make this explicit in code, by
not only making sure that we only pass chat-enabled platforms to this
component but also that we hide it if there's no other platform aside
from the primary that could be set for primary chat. That is such the
case for example when using Twitch as primary and also streaming to
Tiktok.

This reverts commit faa17ea.

TikTok's fake chat component makes other platform chats unable to load
after switching to Tiktok's chat while live. This simplifies Tiktok's
handling by moving logic to the parent component and not rendering a
`Chat` component at all since we don't need to load an URL or setup
resize event listeners, or any of the other functionality we're aware
of. While the code might not be pretty on the caller, getting rid of
render side effects and unrelated code in the `Chat` component that's
already been found to be buggy should be an improvement overall.

…tform-reqs

…tform-reqs

…ry-platform-reqs

Custom destinations aren't really being persisted until we toggle a
platform on or off (which saves settings), or (presumably) when going
live. There's a call to `#save` after switching platforms but no such
call exists for custom destinations.

…m-primary-platform-reqs