OSD collector does not detect encrypted bluestore devices

The code for detecting whether or not an OSD is encrypted does not do any checking if the device is bluestore., it just assumes "encrypted = 0".

One possible fix would be to check the path of the block device, similar to the filestore check:
```
linkpath = os.readlink(block_link)
encrypted = linkpath.startswith('/dev/mapper')
```

Locate the OSD collector's device-encryption detection and compare the existing filestore check with the bluestore path. Confirm that encrypted bluestore devices are recognized through their block-device link, and verify the collector's resulting metric or output for both encrypted and unencrypted devices.

Written by the indexing model from the issue text.