azure/webapps-deploy@v2 not trying to fetch image before reporting deploy as complete

We're using `azure/webapps-deploy@v2` to deploy a docker image, registered in `Azure Container registry` to our `Azure App service`. When running the action, it reports that it deployed the changes, but the instances of the app-service might fail with the following error:

```
2025-06-02T12:23:49.153Z INFO - Pulling image: xxxxxx.azurecr.io/xxxxxx:xxxxxx
2025-06-02T12:23:49.378Z ERROR - DockerApiException: Docker API responded with status code=NotFound, response={"message":"manifest for xxxxxx.azurecr.io/xxxxxx:xxxxxx not found: manifest unknown: manifest tagged by \"xxxxxx\" is not found"}

2025-06-02T12:23:49.489Z ERROR - DockerApiException: Docker API responded with status code=InternalServerError, response={"message":"Head \"https://xxxxxx.azurecr.io/v2/xxxxxx/manifests/xxxxxx\": unauthorized: authentication required, visit https://aka.ms/acr/authorization for more information. CorrelationId: d6fd885c-3389-4d44-9eb8-d9eb5745f1da"}

2025-06-02T12:23:49.490Z WARN - Image pull failed. Defaulting to local copy if present.
2025-06-02T12:23:49.492Z ERROR - Image pull failed: Verify docker image configuration and credentials (if using private repository)
```

Please update the deploy-function to check whether the image can be reached prior to starting a deployment, which might take down everything, because an image with the given tag does not exist.