Update channel member notify props to use native JSON (#18114)

* Update channel member notify props to use native JSON

Created a new store method that patches the notify props field.

https://community-daily.mattermost.com/plugins/focalboard/workspace/zyoahc9uapdn3xdptac6jb69ic?id=285b80a3-257d-41f6-8cf4-ed80ca9d92e5&v=495cdb4d-c13a-4992-8eb9-80cfee2819a4&c=91d08676-4a0e-4f02-8dce-d24d4fc56449

```release-note
NONE
```

* cleanup

```release-note
NONE
```

* forgot to commit

```release-note
NONE
```

* Fix edge case

```release-note
NONE
```

* address review comments

```release-note
NONE
```

* fix incorrect order

```release-note
NONE
```

* Address review comments

```release-note
NONE
```

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

store/timerlayer/timerlayer.go

@@ -2046,6 +2046,22 @@ func (s *TimerLayerChannelStore) UpdateMember(member *model.ChannelMember) (*mod
 	return result, err
 }
 
+func (s *TimerLayerChannelStore) UpdateMemberNotifyProps(channelID string, userID string, props map[string]string) (*model.ChannelMember, error) {
+	start := timemodule.Now()
+
+	result, err := s.ChannelStore.UpdateMemberNotifyProps(channelID, userID, props)
+
+	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.UpdateMemberNotifyProps", success, elapsed)
+	}
+	return result, err
+}
+
 func (s *TimerLayerChannelStore) UpdateMembersRole(channelID string, userIDs []string) error {
 	start := timemodule.Now()