libtracker-sparql: Do not attempt to rebuild non-existing FTS tables

If a database/ontology has no fulltext-indexed properties, we do not
create a corresponding FTS table. Likewise, parser/locale updates
should not attempt to update it, or we will get a "SQL logic error"
poking non-existing tables.

Closes: https://gitlab.gnome.org/GNOME/nautilus/-/issues/2278