StarRocks through 4.0.13 Missing Authorization on DROP MATERIALIZED VIEW for Legacy Synchronous Materialized Views

StarRocks performs no privilege check when a legacy synchronous materialized view is dropped. Every other statement type routed through AuthorizerStmtVisitor calls into Authorizer before execution, but visitDropMaterializedViewStatement returns immediately with a comment stating the check happens in execution logic. That holds only for asynchronous materialized views: LocalMetastore.dropMaterializedView calls Authorizer.checkMaterializedViewAction inside a branch taken when the resolved table is a MaterializedView. A legacy synchronous materialized view is stored as a rollup index on an OlapTable rather than a MaterializedView, so the other branch runs, reaching AlterJobMgr.processDropMaterializedView and MaterializedViewHandler, neither of which contains any Authorizer call. The former locates the target by scanning every OlapTable in the named database for a matching rollup index, and the latter validates only table state and name conflicts. Any authenticated account can therefore drop a legacy synchronous materialized view belonging to any database, holding no grant on the view, the base table or the database, and the drop is indistinguishable from an authorized one.