pasteManager: Catch newly-added gjs exception

gjs 1.58.2 started throwing an exception when encountering a parameter that
is an array of plain structs, as that case is not currently supported.

The exception is overly broad though, and also broke the one case that is
supported: An empty array where the actually struct type isn't relevant.

We cannot fix this in Polari, but at least we can catch the exception to
fail gracefully, so only DND drop target support gets broken instead of
the whole interface.

GNOME/polari#114
5 jobs for !137 with catch-dnd-exception in 9 minutes and 7 seconds (queued for 3 seconds)
detached
Status Name Job ID Coverage
  Commit Check
passed check_commit_log #510543

00:00:20

 
  Source Check
passed eslint #510544

00:00:25

 
  Build
passed flatpak #510545

00:07:35

 
  Review
passed review #510546

00:00:23

passed stop_review #510547
manual

00:00:22