[stable33] fix(files_sharing): don't abort share:list when orphaned shares exist - #64147

`occ share:list` resolved the source node of every share without
handling NotFoundException, so a single orphaned share (e.g. the source
file was deleted from disk externally, or is pending removal by
DeleteOrphanedSharesJob) aborted the whole command with "Node for share
not found" and produced no output at all.
Catch the exception in both places that resolve the share node: orphaned
shares are now listed with a null source-path, and the --parent filter
skips them instead of crashing.
Add unit tests for the command (previously untested), covering listing
with an orphaned share present and the --parent filter with and without
--recursive.
Closes #61949
Assisted-by: ClaudeCode:claude-fable-5
Signed-off-by: Fabio Fantoni <fabio.fantoni@m2r.biz>