Issue with unicode character during "mojo juju-check-wait"

[Benjamin Allot]

Hello,

This error is thrown out when displaying unit status containing some strange unicode character:

Snippet of the mojo output:
```
2021-06-01 13:06:35 [INFO] Waiting up to 1800 seconds for environment to reach steady state (not running any hook), with wait-for-workload set to False
2021-06-01 13:06:37 [ERROR] juju status --format=json failed: 'ascii' codec can't decode byte 0xe2 in position 20807: ordinal not in range(128)
```

I guess this is the kind of message causing the issue:
"message: \u2713 Livepatch server running."

Can be reproduced with a ̀ mojo juju-check-wait`