ci: remove GGUF model verification step from workflow

The step that verified the existence of the GGUF model file has been removed from the GitHub Actions workflow because on windows and linux-musl runners it was failing.
If the file isn’t present, the Makefile’s $(GGUF_MODEL_PATH) rule will download it as before, so we no longer need to enforce the explicit test -f check that was failing in containerized environments.

Author: andinux

.github/workflows/main.yml

@@ -155,9 +155,6 @@ jobs:
           path: ${{ needs.download-model.outputs.model-path }}
           key: ${{ needs.download-model.outputs.cache-key }}
 
-      - name: Verify GGUF model
-        run: test -f "${{ needs.download-model.outputs.model-path }}"
-
       - name: android setup java
         if: matrix.name == 'android-aar'
         uses: actions/setup-java@v4