Add FXIOS-10716 [sponsored tiles] Add telemetry class for unified ads

[lmarceau]

📜 Tickets

Jira ticket
Github issue

💡 Description

Previous telemetry for click and impression on Sponsored tiles was sent through Glean (with the SponsoredTileTelemetry class). With the new unified ads API we need to make a GET request on the callback URLs provided when we request the tiles instead of relying on Glean.

📝 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]

	Messages
📖	Project coverage: 33.99%
📖	Edited 1 files
📖	Created 2 files

Client.app: Coverage: 31.89

File	Coverage
UnifiedAdsCallbackTelemetry.swift	89.13%	✅

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