Bump actions/download-artifact from 6 to 7

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v6...v7)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/gradle.yaml

@@ -181,7 +181,7 @@ jobs:
         with:
           submodules: recursive
 
-      - uses: actions/download-artifact@v6
+      - uses: actions/download-artifact@v7
         with:
           name: 'SlimeVR-Server'
           path: server/desktop/build/libs/
@@ -279,7 +279,7 @@ jobs:
         with:
           submodules: recursive
 
-      - uses: actions/download-artifact@v6
+      - uses: actions/download-artifact@v7
         with:
           name: 'SlimeVR-Server'
           path: server/desktop/build/libs/
@@ -359,7 +359,7 @@ jobs:
         with:
           submodules: recursive
 
-      - uses: actions/download-artifact@v6
+      - uses: actions/download-artifact@v7
         with:
           name: 'SlimeVR-Server'
           path: server/desktop/build/libs/