@W-22954921: [iOS] Stabilize flaky test testMissingLoginHint

[JohnsonEricAtSalesforce]

Draft: Please hold reviews while tests are evaluated, corrected and verified.

[github-actions]

	Tests	Passed ☑️	Skipped	Failed ❌️
SalesforceSDKCore iOS ^26 Test Results	647 ran	644 ✅		3 ❌

Test	Result
SalesforceSDKCore iOS ^26 Test Results
SalesforceRestAPITests.testCreateQuerySearchDelete	❌ failure
SalesforceRestAPITests.testUpdateWithIfUnmodifiedSince	❌ failure
SalesforceRestAPITests.testUploadOwnedFilesDelete	❌ failure

[github-actions]

	Tests	Passed	Skipped	Failed ❌️
AuthFlowTester UI Test Results all	1 ran			1 ❌

Test	Result
AuthFlowTester UI Test Results all
AuthFlowTesterUITests.xctest
LegacyLoginTests.testCAOpaque_DefaultScopes_WebServerFlow()	❌ failure

[github-actions]

	Tests	Passed ☑️	Skipped	Failed ❌️
SalesforceSDKCore iOS ^18 Test Results	647 ran	643 ✅		4 ❌

Test	Result
SalesforceSDKCore iOS ^18 Test Results
testMissingMyDomain()	❌ failure
SalesforceRestAPITests.testCreateQuerySearchDelete	❌ failure
SalesforceRestAPITests.testUpdateWithIfUnmodifiedSince	❌ failure
SalesforceRestAPITests.testUploadOwnedFilesDelete	❌ failure

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.36%. Comparing base (1c73e4c) to head (154a54d).
⚠️ Report is 4 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #4062      +/-   ##
==========================================
+ Coverage   66.65%   68.36%   +1.70%     
==========================================
  Files         246      246              
  Lines       21481    21481              
==========================================
+ Hits        14318    14685     +367     
+ Misses       7163     6796     -367     

Components	Coverage Δ
Analytics	70.78% <ø> (ø)
Common	71.25% <ø> (+0.46%)	⬆️
Core	61.88% <ø> (+2.70%)	⬆️
SmartStore	73.44% <ø> (-0.16%)	⬇️
MobileSync	88.79% <ø> (-0.27%)	⬇️
see 25 files with indirect coverage changes

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