Fix JsonPath error on dkan:datastore:drop-all

[paul-m]

The RootedJsonData query was somehow wrong in this instance. Fixing that is not so hard.

Using the sample content, we also encounter the "Market Value Analysis - Urban Redevelopment Authority" dataset, which does not have distributions that can be imported into the database... Since drop-all now works, it tries to drop non-existent datastores, which halts all progress.

So now dkan:datastore:drop (not drop-all) will catch these exceptions and report them as warnings.

Here's your set of QA commands:

ddev dkan-site-install
ddev drush pm-enable sample_content
ddev drush dkan:sample-content:create
ddev drush cron
ddev drush cron
ddev drush dkan:datastore:drop-all

This should all happen without error, but with warnings for three of the datasets:

 [notice] Successfully dropped the datastore for resource 3a187a87dc6cd47c48b6b4c4785224b7
 [notice] Successfully removed the post import job status for resource 3a187a87dc6cd47c48b6b4c4785224b7
 [warning] Unable to drop datastore for ad62ad1179fa1b0e44c8b9226c2266a8
 [notice] Successfully removed the post import job status for resource ad62ad1179fa1b0e44c8b9226c2266a8
 [warning] Unable to drop datastore for 9f076e2af8927b72db5cf0e05e8cd5f2
 [notice] Successfully removed the post import job status for resource 9f076e2af8927b72db5cf0e05e8cd5f2
 [warning] Unable to drop datastore for 60d78924087b2516acf1e57ff1fc8b83
....etc