Adds support for GMs in shared channels (#31403)

* Adds support for GMs in shared channels

* Fix linter

* Remove creatorID from slack call

---------

Co-authored-by: Miguel de la Cruz <miguel@ctrlz.es>

server/channels/store/storetest/mocks/ChannelStore.go

@@ -2537,9 +2537,16 @@ func (_m *ChannelStore) Restore(channelID string, timestamp int64) error {
 	return r0
 }
 
-// Save provides a mock function with given fields: rctx, channel, maxChannelsPerTeam
-func (_m *ChannelStore) Save(rctx request.CTX, channel *model.Channel, maxChannelsPerTeam int64) (*model.Channel, error) {
-	ret := _m.Called(rctx, channel, maxChannelsPerTeam)
+// Save provides a mock function with given fields: rctx, channel, maxChannelsPerTeam, channelOptions
+func (_m *ChannelStore) Save(rctx request.CTX, channel *model.Channel, maxChannelsPerTeam int64, channelOptions ...model.ChannelOption) (*model.Channel, error) {
+	_va := make([]interface{}, len(channelOptions))
+	for _i := range channelOptions {
+		_va[_i] = channelOptions[_i]
+	}
+	var _ca []interface{}
+	_ca = append(_ca, rctx, channel, maxChannelsPerTeam)
+	_ca = append(_ca, _va...)
+	ret := _m.Called(_ca...)
 
 	if len(ret) == 0 {
 		panic("no return value specified for Save")
@@ -2547,19 +2554,19 @@ func (_m *ChannelStore) Save(rctx request.CTX, channel *model.Channel, maxChanne
 
 	var r0 *model.Channel
 	var r1 error
-	if rf, ok := ret.Get(0).(func(request.CTX, *model.Channel, int64) (*model.Channel, error)); ok {
-		return rf(rctx, channel, maxChannelsPerTeam)
+	if rf, ok := ret.Get(0).(func(request.CTX, *model.Channel, int64, ...model.ChannelOption) (*model.Channel, error)); ok {
+		return rf(rctx, channel, maxChannelsPerTeam, channelOptions...)
 	}
-	if rf, ok := ret.Get(0).(func(request.CTX, *model.Channel, int64) *model.Channel); ok {
-		r0 = rf(rctx, channel, maxChannelsPerTeam)
+	if rf, ok := ret.Get(0).(func(request.CTX, *model.Channel, int64, ...model.ChannelOption) *model.Channel); ok {
+		r0 = rf(rctx, channel, maxChannelsPerTeam, channelOptions...)
 	} else {
 		if ret.Get(0) != nil {
 			r0 = ret.Get(0).(*model.Channel)
 		}
 	}
 
-	if rf, ok := ret.Get(1).(func(request.CTX, *model.Channel, int64) error); ok {
-		r1 = rf(rctx, channel, maxChannelsPerTeam)
+	if rf, ok := ret.Get(1).(func(request.CTX, *model.Channel, int64, ...model.ChannelOption) error); ok {
+		r1 = rf(rctx, channel, maxChannelsPerTeam, channelOptions...)
 	} else {
 		r1 = ret.Error(1)
 	}