`_read_geodataframe` raises `UnboundLocalError` when the file cannot be read

[rajeeja]

• _read_geodataframe catches every read failure, prints it, and falls through, so gdf is never bound and the next line raises UnboundLocalError instead of the real cause.
• Reproduced by reading any shapefile or GeoJSON without pyogrio/fiona installed; the actual message ("requires the 'pyogrio' or 'fiona' package") only reaches stdout.
• Applies to any read failure: bad path, corrupt file, or missing driver all produce the same misleading error.
• Fixed in Raise the underlying cause when geospatial data cannot be read #1694 by removing the try/except entirely, letting geopandas raise its own exception directly.