@W-22954922: [iOS] Stabilize flaky test testCAOpaque_DefaultScopes_WebServerFlow

[JohnsonEricAtSalesforce]

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

[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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.56%. Comparing base (3740bb2) to head (0978242).
⚠️ Report is 5 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #4063      +/-   ##
==========================================
- Coverage   68.39%   66.56%   -1.83%     
==========================================
  Files         246      246              
  Lines       21477    21481       +4     
==========================================
- Hits        14689    14299     -390     
- Misses       6788     7182     +394     

Components	Coverage Δ
Analytics	70.78% <ø> (ø)
Common	71.25% <ø> (+0.46%)	⬆️
Core	59.09% <50.00%> (-2.88%)	⬇️
SmartStore	73.44% <ø> (ø)
MobileSync	88.79% <ø> (ø)
see 22 files with indirect coverage changes

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[github-actions]

	Tests	Passed ☑️	Skipped	Failed ❌️
SalesforceSDKCore iOS ^26 Test Results	647 ran	646 ✅		1 ❌

Test	Result
SalesforceSDKCore iOS ^26 Test Results
testNonCallbackURL()	❌ failure

[github-actions]

	Tests	Passed ☑️	Skipped	Failed ❌️
SalesforceSDKCore iOS ^18 Test Results	647 ran	645 ✅		2 ❌

Test	Result
SalesforceSDKCore iOS ^18 Test Results
testNonCallbackURL()	❌ failure
testAsyncBatchRequestStopOnFailure()	❌ failure