[MM-36995] Start using db native JSON datatypes (#17930)

* Start using db native JSON datatypes

* Fix syntax to work on MySQL 5.7.12

store/sqlstore/user_store.go

@@ -69,13 +69,13 @@ func newSqlUserStore(sqlStore *SqlStore, metrics einterfaces.MetricsInterface) s
 		table.ColMap("FirstName").SetMaxSize(64)
 		table.ColMap("LastName").SetMaxSize(64)
 		table.ColMap("Roles").SetMaxSize(256)
-		table.ColMap("Props").SetMaxSize(4000)
-		table.ColMap("NotifyProps").SetMaxSize(2000)
+		table.ColMap("Props").SetDataType(sqlStore.jsonDataType())
+		table.ColMap("NotifyProps").SetDataType(sqlStore.jsonDataType())
 		table.ColMap("Locale").SetMaxSize(5)
 		table.ColMap("MfaSecret").SetMaxSize(128)
 		table.ColMap("RemoteId").SetMaxSize(26)
 		table.ColMap("Position").SetMaxSize(128)
-		table.ColMap("Timezone").SetMaxSize(256)
+		table.ColMap("Timezone").SetDataType(sqlStore.jsonDataType())
 	}
 
 	return us