* api: return 404 for alloc FS list/stat endpoints
If the alloc filesystem doesn't have a file requested by the List
Files or Stat File API, we currently return a HTTP 500 error with the
expected "file not found" error message. Return a HTTP 404 error
instead.
* update FS Handler
Previously the FS handler would interpret a 500 status as a 404
in the adapter layer by checking if the response body contained
the text or is the response status
was 500 and then throw an error code for 404.
Co-authored-by: Jai Bhagat <jaybhagat841@gmail.com>
This partially addresses #7799.
Task state filesystems are contained within a subdirectory of their
parent allocation, so almost everything that existed for browsing task
state filesystems was applicable to browsing allocations, just without
the task name prepended to the path. I aimed to push this differential
handling into as few contained places as possible.
The tests also have significant overlap, so this includes an extracted
behavior to run the same tests for allocations and task states.
