The current guard spec schematic uses `inject` whereas we dropped it for the service spec a while ago.
This commits updates the guard spec schematic to be similar to the current service spec.
Currently when using `ivy-ngcc` it will print out a warning
```
Failed to read entry point info from //node_modules/@schematics/angular/workspace/files/package.json with error SyntaxError: Unexpected token < in JSON at position 1121.
```
Fixes#13378