Migrate ktfmt check workflow to new builder

Author: Rawa

.github/workflows/android-kotlin-format-check.yml

@@ -19,7 +19,7 @@ permissions: {}
 jobs:
   prepare:
     name: Prepare
-    runs-on: ubuntu-latest
+    runs-on: android-build
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -43,6 +43,12 @@ jobs:
     runs-on: ubuntu-latest
     container:
       image: ${{ needs.prepare.outputs.container_image }}
+      volumes:
+        # node is symlinked in, w/o mounting it, when using a image node won't be found for the
+        # checkout action
+        # https://github.com/NixOS/nixpkgs/issues/306373
+        - /nix:/nix
+        - gradle-cache:/root/.gradle
     steps:
       # Fix for HOME path overridden by GH runners when building in containers, see:
       # https://github.com/actions/runner/issues/863