Refactor FXIOS-9855 #21636 Flaky tests

[lmarceau]

📜 Tickets

Jira ticket
Github issue

💡 Description

Couple of tests changes:

• Introduced DispatchQueueInterface inside CreditCardBottomSheetViewModel to be able to use MockDispatchQueue for unit tests. This makes those test synchronous, which will remove some part of the flakiness hopefully.
• ThrottlerTests were failing for me locally, now using setUp and tearDown to ensure fresh state on each test run.
• func waitForCondition(timeout:condition:) wasn't used, so removing it
• Added file and line to unwrapAsync as I saw some failing tests without knowing on which line exactly it was failing.

📝 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/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]

	Warnings
⚠️	Pull Request size seems relatively large. If this Pull Request contains multiple changes, please split each into separate PR will helps faster, easier review. Consider using epic branches for work that would affect main.

	Messages
📖	Project coverage: 32.83%
📖	Edited 4 files
📖	Created 0 files

Client.app: Coverage: 31.71

File	Coverage
CreditCardBottomSheetViewModel.swift	74.5%	✅

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