ci(flatpak): update build artifact name

Just aligning the name of the Flatpak package with other build artifacts.

Signed-off-by: guihkx <626206+guihkx@users.noreply.github.com>
(cherry picked from commit e0faee7f26)

.github/workflows/build.yml

@@ -640,12 +640,17 @@ jobs:
         uses: actions/checkout@v4
         if: inputs.build_type == 'Debug'
         with:
-          submodules: "true"
+          submodules: true
+
+      - name: Set short version
+        shell: bash
+        run: echo "VERSION=${GITHUB_SHA::7}" >> $GITHUB_ENV
+
       - name: Build Flatpak (Linux)
         if: inputs.build_type == 'Debug'
         uses: flatpak/flatpak-github-actions/flatpak-builder@v6
         with:
-          bundle: "Prism Launcher.flatpak"
+          bundle: PrismLauncher-${{ runner.os }}-${{ env.VERSION }}-Flatpak.flatpak
           manifest-path: flatpak/org.prismlauncher.PrismLauncher.yml
 
   nix: