R1:b352cae97de4

Don't stop on read-only mode for read-only storage workflows

Summary:
Fixes T11042. Currently, all `bin/storage` workflows stop if `cluster.read-only` is set:

```
$ ./bin/storage adjust
Usage Exception: Phabricator is currently in read-only mode. Use --force to override this mode.
```

However, some of them (`status`, `dump`, `databases`, etc) are read-only anyway and safe to run. Don't prompt in these cases.

Test Plan:
- Set `cluster.read-only` to `true`.
- Ran `bin/storage dump`, `bin/storage…