[MM-56904] Reduce the number of api requests made to fetch user information for GMs on page load (#27149)

* use new endpoint to fetch group members

server/channels/jobs/delete_dms_preferences_migration/delete_dms_preferences_migration.go

@@ -0,0 +1,43 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package delete_dms_preferences_migration
+
+import (
+	"time"
+
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/v8/channels/jobs"
+	"github.com/mattermost/mattermost/server/v8/channels/store"
+	"github.com/pkg/errors"
+)
+
+const (
+	timeBetweenBatches = 1 * time.Second
+)
+
+// MakeWorker creates a batch migration worker to delete empty drafts.
+func MakeWorker(jobServer *jobs.JobServer, store store.Store, app jobs.BatchMigrationWorkerAppIFace) model.Worker {
+	return jobs.MakeBatchMigrationWorker(
+		jobServer,
+		store,
+		app,
+		model.MigrationKeyDeleteDmsPreferences,
+		timeBetweenBatches,
+		doDeleteDmsPreferencesMigrationBatch,
+	)
+}
+
+// doDeleteDmsPreferencesMigrationBatch deletes any limit_visible_dms_gms preferences with a value > 40 and less than 1.
+func doDeleteDmsPreferencesMigrationBatch(data model.StringMap, store store.Store) (model.StringMap, bool, error) {
+	rowAffected, err := store.Preference().DeleteInvalidVisibleDmsGms()
+	if err != nil {
+		return nil, false, errors.Wrapf(err, "failed to delete invalid limit_visible_dms_gms")
+	}
+
+	if rowAffected == 0 {
+		return nil, true, nil
+	}
+
+	return nil, false, nil
+}

server/channels/jobs/delete_dms_preferences_migration/delete_dms_preferences_migration_test.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package delete_dms_preferences_migration
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/mattermost/mattermost/server/v8/channels/store/storetest"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDoDeleteDMsPreferencesMigrationBatch(t *testing.T) {
+	t.Run("failure deleting batch", func(t *testing.T) {
+		mockStore := &storetest.Store{}
+		t.Cleanup(func() {
+			mockStore.AssertExpectations(t)
+		})
+
+		mockStore.PreferenceStore.On("DeleteInvalidVisibleDmsGms").Return(int64(0), errors.New("failure"))
+
+		data, done, err := doDeleteDmsPreferencesMigrationBatch(nil, mockStore)
+		require.EqualError(t, err, "failed to delete invalid limit_visible_dms_gms: failure")
+		assert.False(t, done)
+		assert.Nil(t, data)
+	})
+
+	t.Run("do batches", func(t *testing.T) {
+		mockStore := &storetest.Store{}
+		t.Cleanup(func() {
+			mockStore.AssertExpectations(t)
+		})
+
+		mockStore.PreferenceStore.On("DeleteInvalidVisibleDmsGms").Return(int64(10), nil)
+
+		data, done, err := doDeleteDmsPreferencesMigrationBatch(nil, mockStore)
+		require.NoError(t, err)
+		assert.False(t, done)
+		assert.Nil(t, data)
+	})
+
+	t.Run("done batches", func(t *testing.T) {
+		mockStore := &storetest.Store{}
+		t.Cleanup(func() {
+			mockStore.AssertExpectations(t)
+		})
+
+		mockStore.PreferenceStore.On("DeleteInvalidVisibleDmsGms").Return(int64(0), nil)
+
+		data, done, err := doDeleteDmsPreferencesMigrationBatch(nil, mockStore)
+		require.NoError(t, err)
+		assert.True(t, done)
+		assert.Nil(t, data)
+	})
+}