[web] Fix warning - set readOnly param to EnumSettingOption radio

Summary:
Fixing warning that occur on controlled radio input in EnumSettingsOption

Warning communiqué:

Test Plan:

1. Open console
2. Open any modal that uses EnumSettingOption (e.g. channel notification modal)
3. Now, this warning doesn't appear

Reviewers: tomek, atul

Reviewed By: atul

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5110