Edit UI: remove obsolete feature flags

The Business Edit UI code still uses some feature flags, which I believe are now obsolete. This ticket is to:
- [ ] delete obsolete FF from the code
- [ ] check other UIs to see if they use these FF; if so, create a new ticket to delete those
- [ ] delete obsolete FF from LaunchDarkly **only AFTER the code changes are done, otherwise some features will be unavailable**

Ie,
```
const defaultFlagSet: LDFlagSet = {
'alteration-ui-enabled': false,
'change-ui-enabled': false,
'conversion-ui-enabled': false,
'correction-ui-enabled': false
}
```