Add FXIOS-10525 [Sent from Firefox] Add new settings toggle for the Sent From Firefox share test

[ih-codes]

:scroll: Tickets

Jira ticket Github issue

:bulb: Description

This PR adds a new toggle to the Settings screen to enable or disable the Sent from Firefox feature ("Include Firefox Download Link...")

This toggle only appears if you have enabled Sent from Firefox from the debug settings. It should disappear from Settings if the feature flag is disabled.

:pencil: Checklist

You have to check all boxes before merging

• [x] Filled in the above information (tickets numbers and description of your work)
• [x] Updated the PR name to follow our PR naming guidelines
• [ ] Wrote unit tests and/or ensured the tests suite is passing
• [x] When working on UI, I checked and implemented accessibility (minimum Dynamic Text and VoiceOver)
• [ ] If needed, I updated documentation / comments for complex code and public methods
• [ ] If needed, added a backport comment (example @Mergifyio backport release/v120)

[mobiletest-ci-bot]

	Messages
:book:	Project coverage: 32.88%
:book:	Edited 4 files
:book:	Created 1 files

Client.app: Coverage: 30.92

File	Coverage
SentFromFirefoxSetting.swift	0.0%	⚠️
AppSettingsTableViewController.swift	25.67%	⚠️

Generated by :no_entry_sign: Danger Swift against 145aa791b8fb5d5d09070af5382bf06cf45834e0