[MM-7968] restrict creation of direct channels to team members (#17222)

* restrict creation of direct channels to team members

* run make i18n-extract

* add suggestions from hahmadia

* place common-team-check logic in app layer

* use flat SQL query

* show more specific error message to user

* MM-7968: Fmt file.

* MM-7968: Fix for moved session field.

Co-authored-by: Max Erenberg <max.erenberg@mattermost.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Martin Kraft <martinkraft@gmail.com>
Co-authored-by: Martin Kraft <martin@upspin.org>

store/opentracinglayer/opentracinglayer.go

@@ -8061,6 +8061,24 @@ func (s *OpenTracingLayerTeamStore) GetChannelUnreadsForTeam(teamID string, user
 	return result, err
 }
 
+func (s *OpenTracingLayerTeamStore) GetCommonTeamIDsForTwoUsers(userID string, otherUserID string) ([]string, error) {
+	origCtx := s.Root.Store.Context()
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "TeamStore.GetCommonTeamIDsForTwoUsers")
+	s.Root.Store.SetContext(newCtx)
+	defer func() {
+		s.Root.Store.SetContext(origCtx)
+	}()
+
+	defer span.Finish()
+	result, err := s.TeamStore.GetCommonTeamIDsForTwoUsers(userID, otherUserID)
+	if err != nil {
+		span.LogFields(spanlog.Error(err))
+		ext.Error.Set(span, true)
+	}
+
+	return result, err
+}
+
 func (s *OpenTracingLayerTeamStore) GetMember(ctx context.Context, teamID string, userID string) (*model.TeamMember, error) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "TeamStore.GetMember")