Revert "Specify personal-file interface for snap"

This reverts commit 2641a37.

This was reverted due to errors in the snap publishing pipeline:
interface 'starship-config' not found in base declaration declaration-snap-v2_plug_known (starship-config, starship-config)
invalid plugs interface definition 'starship-config' lint-snap-v2_app_plugs_plug_reference (starship, starship-config)
unknown interface 'starship-config' lint-snap-v2_plugs (starship-config, starship-config)

snapcraft.yaml

@@ -74,20 +74,13 @@ parts:
       snapcraftctl build
       snapcraftctl set-version $(git -C ../src describe --tags  | sed 's/v//')
 
-plugs:
-  starship-config:
-    interfaces: personal-files
-    write:
-      - $HOME/.config/starship.toml
-      - $HOME/.cache/starship
-
 apps:
   starship:
     command: bin/starship
     plugs:
       - home
       - removable-media
-      - starship-config
+      - personal-files
 
 architectures:
   - build-on: amd64