Fixes#128751.
As asset libraries were added or removed (through the UI or BPY), the
"All" asset library wouldn't refresh to reflect the changes. In general
this wasn't handled well. Even a manual refresh wouldn't give the right
result.
There were multiple issues really:
- Only the first load of the "All" library would query the preferences
for the available libraries. Further loads would only refresh the
catalogs, ignoring any added/removed libraries.
- Operators and BPY functions didn't clear the asset libraries to
enforce a re-fetch.
- When clearing an asset library, the "All" library wasn't cleared in
some cases, it would show the old state still.
- The API function to clear an asset library's asset list would not
clear the storage of asset browsers so they wouldn't refresh. It makes
no sense to only do one, so let the API handle both cases.
The way we handle asset library updating could be improved generally,
and be more internal to the asset system. For now this explicit clearing
seems fine.
We also need to handle removal of libraries better still, I think they
remain in memory.
Pull Request: https://projects.blender.org/blender/blender/pulls/129541
a859ed1130