Based on QgsProviderSublayerDetails, this new dialog nicely handles
mixed layer type files (e.g. mixed vector/raster/mesh layer formats).
It also:
- Resolves geometry types in a background thread, to avoid lengthy
application hangs whenever a full table scan is required to determine
available geometry types
- Shows a handy search filter box for filtering sublayers to matching
strings
- Shows icons representing sublayer types
- Has an interactive label showing the file path which can be clicked
to open a file explorer focused on the file
