Crash report cohort ID support for iOS

[jdjackson]

Task/Issue URL: https://app.asana.com/0/1208592102886666/1208759541597499/f
Tech Design URL: https://app.asana.com/0/1208592102886666/1208660326715650/f

Description:
DO NOT MERGE - this is a draft for input, not ready to go live yet.

iOS client support for CRCID send/receive (primarily supported in BSK, with changes under review in BSK #1116). This is pretty straightforward, just conforming to CrashCollection’s new init signature, and clearing CRCIDs when the user opts out of crash reporting. BSK handles everything else.

Steps to test this PR:
Note: Must be tested on a physical device, as the simulator does not produce crash logs (and thus doesn’t find and upload them either).

To cause and report a crash:

1. Launch the app and force a crash, which can be done from Settings → All Debug Options → Crash (fatal error) or similar. Note that Crash (CPU/Memory) does not appear to produce a crash log, and thus won’t trigger crash uploading.
2. Launch the app again (easiest with a debugger)
3. For the first crash of an app install: You will be prompted to opt in or out of crash reporting when the app is launched. Opt in and watch logs for “crcid” and you should see logs from CrashReportSender:56, and CrashCollection:95-109.
4. On subsequent crashes, when opted in, you should see statements confirming the received crcid was sent, and that the server returned either the same matching one, or a new one (in which case the new one should be stored and used on subsequent crash reports)

To test clearing of the crcid when opting out:

1. Navigate to Settings → About and switch “Send Crash Reports” off, then back on again (this step should clear the crcid)
2. Follow steps from “To cause and report a crash” above, and confirm that the crash is submitted without an initial crcid, and that the server assigns one and it is stored (causing and uploading a second crash should confirm this new value is used on send).

Definition of Done (Internal Only):

• Does this PR satisfy our Definition of Done?

Copy Testing: N/A

• Use of correct apostrophes in new copy, ie ’ rather than ’

Orientation Testing: N/A

• Portrait
• Landscape

Device Testing:

• iPhone SE (1st Gen)
• iPhone 8
• iPhone X
• iPhone 14 Pro
• iPhone 15 Pro
• iPad

OS Testing:

• iOS 15
• iOS 16
• iOS 17
• iOS 18

Theme Testing: N/A

• Light theme
• Dark theme

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Internal references:

Software Engineering Expectations
Technical Design Template