[MM-37984] Allow Desktop App to authenticate via external providers outside of the app on supported servers (#23795)

* WIP

* Add rate limiting for desktop token API

* Missing mocks

* Style fixes

* Update snapshots

* Maybe use an actual redirect link :P

* Refactoring for tests

* Add tests for server

* Fix lint issue

* Fix tests

* Fix lint

* Add front-end screen component

* Component logic

* Style changes

* Quick style fix

* Lint fixes

* Initial PR feedback

* Enable logging into the browser as well when completing the login process

* Refactor to push more logic to the other component

* Remove unnecessary helper code

* Fix i18n

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/store/storetest/store.go

@@ -61,6 +61,7 @@ type Store struct {
 	PostAcknowledgementStore        mocks.PostAcknowledgementStore
 	PostPersistentNotificationStore mocks.PostPersistentNotificationStore
 	TrueUpReviewStore               mocks.TrueUpReviewStore
+	DesktopTokensStore              mocks.DesktopTokensStore
 }
 
 func (s *Store) SetContext(context context.Context)                { s.context = context }
@@ -103,6 +104,7 @@ func (s *Store) ChannelMemberHistory() store.ChannelMemberHistoryStore {
 	return &s.ChannelMemberHistoryStore
 }
 func (s *Store) TrueUpReview() store.TrueUpReviewStore   { return &s.TrueUpReviewStore }
+func (s *Store) DesktopTokens() store.DesktopTokensStore { return &s.DesktopTokensStore }
 func (s *Store) NotifyAdmin() store.NotifyAdminStore     { return &s.NotifyAdminStore }
 func (s *Store) Group() store.GroupStore                 { return &s.GroupStore }
 func (s *Store) LinkMetadata() store.LinkMetadataStore   { return &s.LinkMetadataStore }
@@ -176,5 +178,6 @@ func (s *Store) AssertExpectations(t mock.TestingT) bool {
 		&s.PostPriorityStore,
 		&s.PostAcknowledgementStore,
 		&s.PostPersistentNotificationStore,
+		&s.DesktopTokensStore,
 	)
 }