qa/suites/crimson-rados/singleton: add install task

qa/suites/crimson-rados/singleton: add install task

This should fix the chmod 777 /var/log/ceph failures.

We were missing the install task which resulted in no /var/log/ceph:
```
2025-07-07T08:55:44.586 INFO:teuthology.run_tasks:Running task ceph...
2025-07-07T08:55:44.679 INFO:tasks.ceph:Making ceph log dir writeable by
non-root...
2025-07-07T08:55:44.679 DEBUG:teuthology.orchestra.run.smithi144:> sudo
chmod 777 /var/log/ceph
2025-07-07T08:55:44.711
INFO:teuthology.orchestra.run.smithi144.stderr:chmod: cannot access
'/var/log/ceph': No such file or directory
```

Signed-off-by: Matan Breizman <mbreizma@redhat.com>