[MM-15302] Migrate Preference.Delete to Sync by default #10715 (#11101)

* MM-15302: Migrate `Preference.Delete` to Sync by default #10715

* MM-15302: Migrate `Preference.Delete` to Sync by default #10715

* regenerate store mocks

* fix shadow var

store/storetest/mocks/PreferenceStore.go

@@ -6,7 +6,6 @@ package mocks
 
 import mock "github.com/stretchr/testify/mock"
 import model "github.com/mattermost/mattermost-server/model"
-import store "github.com/mattermost/mattermost-server/store"
 
 // PreferenceStore is an autogenerated mock type for the PreferenceStore type
 type PreferenceStore struct {
@@ -37,15 +36,15 @@ func (_m *PreferenceStore) CleanupFlagsBatch(limit int64) (int64, *model.AppErro
 }
 
 // Delete provides a mock function with given fields: userId, category, name
-func (_m *PreferenceStore) Delete(userId string, category string, name string) store.StoreChannel {
+func (_m *PreferenceStore) Delete(userId string, category string, name string) *model.AppError {
 	ret := _m.Called(userId, category, name)
 
-	var r0 store.StoreChannel
-	if rf, ok := ret.Get(0).(func(string, string, string) store.StoreChannel); ok {
+	var r0 *model.AppError
+	if rf, ok := ret.Get(0).(func(string, string, string) *model.AppError); ok {
 		r0 = rf(userId, category, name)
 	} else {
 		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(store.StoreChannel)
+			r0 = ret.Get(0).(*model.AppError)
 		}
 	}