Remove Remember Me from production and only expose through dev settings

### What is this about?

This issue tracks removing the Remember Me option altogether for the following reasons:
- Remember Me negates the effect of auto lock timer since remember me will just auto unlock anyways
- Remember Me behavior is essentially the same as auto lock timer = never
- Reduces both the complexity of the auth flow for both code and UX

Thread - https://consensys.slack.com/archives/C06FXU326RL/p1743783730535399?thread_ts=1743541401.398509&cid=C06FXU326RL

While we want to remove this for prod apps, this option will still exist as a developer feature as visualized in this Figma - https://www.figma.com/design/AF8hdmRBQaqqUSWM9tSe1q/Settings-Redesign?node-id=1041-6826&t=P5EP5yqC9RxQoxg4-0

### Scenario
_No response_

### Design

_No response_

### Technical Details

- Remove prod code related to Remember Me from
- Settings
- Login
- Anywhere that has lingering artifacts

- Re-implement in dev settings
- Should not conflict with autolock or any other auth configurations

### Threat Modeling Framework

_No response_

### Acceptance Criteria

_No response_

- Remember Me no longer appears as an option on Login and Settings screen

### Stakeholder review needed before the work gets merged

- [ ] Engineering (needed in most cases)
- [ ] Design
- [ ] Product
- [ ] QA (automation tests are required to pass before merging PRs but not all changes are covered by automation tests - please review if QA is needed beyond automation tests)
- [ ] Security
- [ ] Legal
- [ ] Marketing
- [ ] Management (please specify)
- [ ] Other (please specify)

### References

Slack thread - https://consensys.slack.com/archives/C06FXU326RL/p1743783730535399?thread_ts=1743541401.398509&cid=C06FXU326RL

Start by locating Remember Me references in the Login and Settings screens, then compare the intended developer-only behavior with the linked Figma design. Trace the related authentication configuration and verify that production screens no longer expose the option while developer settings retain it without conflicting with autolock.

Written by the indexing model from the issue text.