Run the mosaic models with the LTS version too

To be done after v3.23 is released, v3.16 is too old to run the tests. One can determine if a model runs with the LTS version manually with the following command:
```bash
$ sudo docker run --rm -ti -v /home/michele/mosaic:/io openquake/engine:3.16 \
"OQ_SAMPLE_SITES=.01 oq run /io/ALS/in/job_vs30.ini -p export_dir=/tmp"
```