[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/store/storetest/mocks/PreferenceStore.go

@@ -96,6 +96,34 @@ func (_m *PreferenceStore) DeleteCategoryAndName(category string, name string) e
 	return r0
 }
 
+// DeleteInvalidVisibleDmsGms provides a mock function with given fields:
+func (_m *PreferenceStore) DeleteInvalidVisibleDmsGms() (int64, error) {
+	ret := _m.Called()
+
+	if len(ret) == 0 {
+		panic("no return value specified for DeleteInvalidVisibleDmsGms")
+	}
+
+	var r0 int64
+	var r1 error
+	if rf, ok := ret.Get(0).(func() (int64, error)); ok {
+		return rf()
+	}
+	if rf, ok := ret.Get(0).(func() int64); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(int64)
+	}
+
+	if rf, ok := ret.Get(1).(func() error); ok {
+		r1 = rf()
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // DeleteOrphanedRows provides a mock function with given fields: limit
 func (_m *PreferenceStore) DeleteOrphanedRows(limit int) (int64, error) {
 	ret := _m.Called(limit)