[MM-36472] Fix inconsistencies in Roles columns (#18390)

* Fix inconsistencies in Roles columns

* Add new migrations

store/sqlstore/user_store.go

@@ -68,7 +68,7 @@ func newSqlUserStore(sqlStore *SqlStore, metrics einterfaces.MetricsInterface) s
 		table.ColMap("Nickname").SetMaxSize(64)
 		table.ColMap("FirstName").SetMaxSize(64)
 		table.ColMap("LastName").SetMaxSize(64)
-		table.ColMap("Roles").SetMaxSize(256)
+		table.ColMap("Roles").SetMaxSize(model.UserRolesMaxLength)
 		table.ColMap("Props").SetDataType(sqlStore.jsonDataType())
 		table.ColMap("NotifyProps").SetDataType(sqlStore.jsonDataType())
 		table.ColMap("Locale").SetMaxSize(5)