Hotspot Password can be too short

[lrnselfreliance]

A user can input a hotspot password which is too short.

1. Modify wrolpi.root_api.update_settings to refuse a password if it is less than 8 characters (HTTP 400).
2. Modify React Settings component to refuse to submit the form if the password is less than 8 characters.
3. Modify wrolpi.test.test_root_api.test_hotspot_settings to test that the endpoint returns the correct error.

[swarajsahil]

Assign it to me i try to solve it

[lrnselfreliance]

Fixed fdaaa51