Refactor FXIOS-9085 #20125 Rename legacy class to top tabs

[lmarceau]

:scroll: Tickets

Jira ticket Github issue

:bulb: Description

Renaming LegacyTabDisplayManager to TopTabDisplayManager since this class is only used in top tabs now. This also wasn't part of the tab tray refactor, so AFAIK this class will stay as is for now.

: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
• [X] Wrote unit tests and/or ensured the tests suite is passing
• [ ] 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: 33.25%
:book:	Edited 3 files
:book:	Created 0 files

Client.app: Coverage: 31.36

File	Coverage
TopTabsViewController.swift	0.0%	⚠️
TopTabDisplayManager.swift	0.0%	⚠️

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