query processor: treat view changes at least as table changes

When a base table changes and altered, so does the views that might
refer to the added column (which includes "SELECT *" views and also
views that might need to use this column for rows lifetime (virtual
columns).
However the query processor implementation for views change notification
was an empty function.
Since views are tables, the query processor needs to at least treat them
as such (and maybe in the future, do also some MV specific stuff).
This commit adds a call to `on_update_column_family` from within
`on_update_view`.
The side effect true to this date is that prepared statements for views
which changed due to a base table change will be invalidated.

Fixes scylladb#16392

Signed-off-by: Eliran Sinvani <eliransin@scylladb.com>

cql3/query_processor.cc

@@ -1084,6 +1084,9 @@ void query_processor::migration_subscriber::on_update_aggregate(const sstring& k
 void query_processor::migration_subscriber::on_update_view(
         const sstring& ks_name,
         const sstring& view_name, bool columns_changed) {
+    // scylladb/scylladb#16392 - Materialized views are also tables so we need at least handle
+    // them as such when changed.
+    on_update_column_family(ks_name, view_name, columns_changed);
 }
 
 void query_processor::migration_subscriber::on_update_tablet_metadata() {