fix: always include filtered matrix item in cache key

[pdecat]

Without this PR, when using matrix items (that I'm adding to the OVH plugin in francois2metz/steampipe-plugin-ovh#74), queries such as the following are missing items when removing the filtered matrix item column, and clearing the cache resolves the issue:

> select name, region from ovh_perso.ovh_cloud_storage_s3 where project_id = '2cf14530bc1e4ba5a3ae44fbd4cbe866' and region = 'GRA'
+---------------+--------+
| name          | region |
+---------------+--------+
| test-pdecat-1 | GRA    |
+---------------+--------+
1 row

> select name, region from ovh_perso.ovh_cloud_storage_s3 where project_id = '2cf14530bc1e4ba5a3ae44fbd4cbe866'
+---------------+--------+
| name          | region |
+---------------+--------+
| test-pdecat-1 | GRA    |
+---------------+--------+
1 row

> .cache clear
> select name, region from ovh_perso.ovh_cloud_storage_s3 where project_id = '2cf14530bc1e4ba5a3ae44fbd4cbe866'
+---------------+-------------+
| name          | region      |
+---------------+-------------+
| test-pdecat-1 | GRA         |
| test-pdecat-3 | EU-WEST-PAR |
+---------------+-------------+
2 rows

[github-actions]

This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[pdecat]

Still current.

[pskrbasu]

Fix looks good to me - very surgical and correct. Thanks @pdecat!