Refactor FXIOS-5343 [v117] Remove qos definitions where not needed

[OrlaM]

📜 Tickets

Jira ticket
Github issue

💡 Description

We have many warnings with conflicting qos priorities on threads, this PR sets everything that doesn't have a good reason for specifiying a qos to use the default.

📝 Checklist

You have to check all boxes before merging

• Filled in the above information (tickets numbers and description of your work)
• Updated the PR name to follow our PR naming guidelines
• Wrote unit tests and ensured the tests suite is passing
• Implemented accessibility and tested on UI related work (minimum Dynamic Text and VoiceOver)
• Updated documentation / comments for complex code and public methods if needed

[mobiletest-ci-bot]

	Messages
📖	Project coverage: 36.15%
📖	Edited 19 files
📖	Created 0 files

Client.app: Coverage: 34.99

File	Coverage
LegacyTabManager.swift	50.23%	✅
TopSitesProvider.swift	99.21%	✅
MainMenuActionHelper.swift	32.89%	⚠️
AccountSyncHandler.swift	86.96%	✅
TopSitesDataAdaptor.swift	99.57%	✅
HistoryDeletionUtility.swift	99.26%	✅
AppLaunchUtil.swift	0.0%	⚠️
DispatchQueueHelper.swift	33.33%	⚠️
Clearables.swift	0.0%	⚠️
BrowserViewController.swift	28.43%	⚠️
NotificationSurfaceManager.swift	77.5%	✅
SearchTermGroupsUtility.swift	91.6%	✅
HistoryPanelViewModel.swift	84.68%	✅

CredentialProvider.appex: Coverage: 17.51

File	Coverage
DispatchQueueHelper.swift	33.33%	⚠️

libAccount.a: Coverage: 51.08

File	Coverage
RustFirefoxAccounts.swift	22.78%	⚠️

libStorage.a: Coverage: 59.86

File	Coverage
SwiftData.swift	62.34%	✅

Generated by 🚫 Danger Swift against c70d022