[PM-37072] chore: Consolidate MockAuthClient with support for MockRegistrationClientProtocol

[matt-livefront]

🎟️ Tracking

PM-37072

📔 Objective

This consolidates MockAuthClient to BitwardenKit and adds a MockRegistrationClientProtocol.

The current MockAuthClient conforms to AuthClientProtocol. When the SDK builds protocols for services, the protocol methods return the concrete type instead of a protocol type (e.g. AuthClientProtocol returns RegistrationClient instead of RegistrationClientProtocol). This makes it difficult to use SDK's protocols directly when they return other types which need to be mocked. As a workaround, this adds an AuthClientService protocol which returns a RegistrationClientProtocol, and then AuthClient can conform to that. This allows for mocking RegistrationClient without too much overhead. The AuthClientService protocol just needs to be used in place of AuthClientProtocol.

[github-actions]

🤖 Bitwarden Claude Code Review

Overall Assessment: APPROVE

This PR consolidates two duplicate MockAuthClient definitions (one in BitwardenShared, one in AuthenticatorShared) into a single public mock in BitwardenKitMocks, and introduces a new AuthClientService protocol in BitwardenKit that mirrors BitwardenSdk.AuthClientProtocol but returns RegistrationClientProtocol so the registration client can finally be mocked. The change wires BitwardenSdkMocks into BitwardenKitMocks so MockRegistrationClientProtocol is available, follows the same extension Client: BitwardenSdkClient shadowing pattern already used for auth()/crypto()/etc., and adjusts the ErrorReportBuilderTests snapshots to include the new BitwardenSdkMocks binary image. No production behavior changes — this is purely a test-infrastructure refactor.

Code Review Details

No findings.

[codecov]

Codecov Report

❌ Patch coverage is 88.40580% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.33%. Comparing base (010f65e) to head (f736eed).

Files with missing lines	Patch %	Lines
.../Core/Auth/Services/SDK/Mocks/MockAuthClient.swift	93.49%	8 Missing ⚠️
...rShared/Core/Platform/Services/ClientService.swift	0.00%	3 Missing ⚠️
...Kit/Core/Auth/Services/SDK/AuthClientService.swift	0.00%	3 Missing ⚠️
...tform/Services/TestHelpers/MockClientService.swift	0.00%	1 Missing ⚠️
...nShared/Core/Platform/Services/ClientService.swift	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2638      +/-   ##
==========================================
- Coverage   87.35%   86.33%   -1.02%     
==========================================
  Files        1919     2144     +225     
  Lines      170962   185355   +14393     
==========================================
+ Hits       149336   160018   +10682     
- Misses      21626    25337    +3711     

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[fedemkr]

🤔 Could we use Sourcery for this? And nonetheless, shouldn't this be named MockAuthClientService?

[matt-livefront]

We could, yes, this PR was already getting large so I was trying to limit the amount of changes. I have these changes on another branch, so ok if I do this as a follow-up PR?

[fedemkr]

Sure no problem