fix: dropbox source connector file path bugs (#3189)
The Dropbox source connector currently raises exceptions when indexing
files due to two issues: a path formatting idiosyncrasy of the Dropbox
library and a divergence in the definition of the Dropbox libraries
fs.info method, expecting a 'url' parameter rather than 'path'.
## Changes
* add a `/` prefix to file path used by DropboxIndexer
* override the fsspec sterilize_info method in DropboxIndexer to call
`self.fs.info` with `url` rather than `path`; to accommodate for the
fact that `dropboxdrivefs` diverges with this signature
* remove `dropbox.sh` from ignored source tests
* update test fixtures (now that the dropbox connector has been fixed
and not skipped)
## Testing
`dropbox.sh` source ingest test now succeeds (and is no longer ignored)
---------
Co-authored-by: ryannikolaidis <ryannikolaidis@users.noreply.github.com>
Co-authored-by: Christine Straub <christinemstraub@gmail.com>
