fix(fill_db_data.py): paged query test did insert before table schema
fix(fill_db_data.py): paged query test did insert before table schema

was fully propagated.
very clear in the logs that insert started, but the schema is
not fully sync'ed. Adding `wait_for_schema_agreement()` should
ensure we will have the schemas fully sync'ed before we start
inserting data into that new table.

scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-longevity-tests