Migrating Emoji store to use sqlx (#18301)

* Migrating Emoji store to use sqlx

https://community-daily.mattermost.com/boards/workspace/zyoahc9uapdn3xdptac6jb69ic/285b80a3-257d-41f6-8cf4-ed80ca9d92e5/495cdb4d-c13a-4992-8eb9-80cfee2819a4?c=646cee9a-219c-49f3-8e0b-6ec2cff4deba

```release-note
NONE
```

* Incorporate review suggestions

```release-note
NONE
```

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

store/sqlstore/context.go

@@ -42,3 +42,11 @@ func (ss *SqlStore) DBFromContext(ctx context.Context) *gorp.DbMap {
 	}
 	return ss.GetReplica()
 }
+
+// DBXFromContext is a helper utility that returns the sqlx DB handle from a given context.
+func (ss *SqlStore) DBXFromContext(ctx context.Context) *sqlxDBWrapper {
+	if hasMaster(ctx) {
+		return ss.GetMasterX()
+	}
+	return ss.GetReplicaX()
+}