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.
Fixes #114 (moved)