MM-43144: Add teams loader (#19960)

```release-note
NONE
```

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/app_iface.go

@@ -742,6 +742,7 @@ type AppIface interface {
 	GetTeamPoliciesForUser(userID string, offset, limit int) (*model.RetentionPolicyForTeamList, *model.AppError)
 	GetTeamStats(teamID string, restrictions *model.ViewUsersRestrictions) (*model.TeamStats, *model.AppError)
 	GetTeamUnread(teamID, userID string) (*model.TeamUnread, *model.AppError)
+	GetTeams(teamIDs []string) ([]*model.Team, *model.AppError)
 	GetTeamsForRetentionPolicy(policyID string, offset, limit int) (*model.TeamsWithCount, *model.AppError)
 	GetTeamsForScheme(scheme *model.Scheme, offset int, limit int) ([]*model.Team, *model.AppError)
 	GetTeamsForSchemePage(scheme *model.Scheme, page int, perPage int) ([]*model.Team, *model.AppError)

app/opentracing/opentracing_layer.go

@@ -9332,6 +9332,28 @@ func (a *OpenTracingAppLayer) GetTeamUnread(teamID string, userID string) (*mode
 	return resultVar0, resultVar1
 }
 
+func (a *OpenTracingAppLayer) GetTeams(teamIDs []string) ([]*model.Team, *model.AppError) {
+	origCtx := a.ctx
+	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetTeams")
+
+	a.ctx = newCtx
+	a.app.Srv().Store.SetContext(newCtx)
+	defer func() {
+		a.app.Srv().Store.SetContext(origCtx)
+		a.ctx = origCtx
+	}()
+
+	defer span.Finish()
+	resultVar0, resultVar1 := a.app.GetTeams(teamIDs)
+
+	if resultVar1 != nil {
+		span.LogFields(spanlog.Error(resultVar1))
+		ext.Error.Set(span, true)
+	}
+
+	return resultVar0, resultVar1
+}
+
 func (a *OpenTracingAppLayer) GetTeamsForRetentionPolicy(policyID string, offset int, limit int) (*model.TeamsWithCount, *model.AppError) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetTeamsForRetentionPolicy")

app/team.go

@@ -741,6 +741,21 @@ func (a *App) GetTeam(teamID string) (*model.Team, *model.AppError) {
 	return team, nil
 }
 
+func (a *App) GetTeams(teamIDs []string) ([]*model.Team, *model.AppError) {
+	teams, err := a.ch.srv.teamService.GetTeams(teamIDs)
+	if err != nil {
+		var nfErr *store.ErrNotFound
+		switch {
+		case errors.As(err, &nfErr):
+			return nil, model.NewAppError("GetTeam", "app.team.get.find.app_error", nil, nfErr.Error(), http.StatusNotFound)
+		default:
+			return nil, model.NewAppError("GetTeam", "app.team.get.finding.app_error", nil, err.Error(), http.StatusInternalServerError)
+		}
+	}
+
+	return teams, nil
+}
+
 func (a *App) GetTeamByName(name string) (*model.Team, *model.AppError) {
 	team, err := a.Srv().Store.Team().GetByName(name)
 	if err != nil {

app/teams/teams.go

@@ -33,6 +33,15 @@ func (ts *TeamService) GetTeam(teamID string) (*model.Team, error) {
 	return team, nil
 }
 
+func (ts *TeamService) GetTeams(teamIDs []string) ([]*model.Team, error) {
+	teams, err := ts.store.GetMany(teamIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	return teams, nil
+}
+
 // CreateDefaultChannels creates channels in the given team for each channel returned by (*App).DefaultChannelNames.
 //
 func (ts *TeamService) createDefaultChannels(teamID string) ([]*model.Channel, error) {