test(W-23836436): add non-DPoP pool server login test to ECALoginTests

[wmathurin]

Summary

• Adds test_givenNoDPoP_whenLoginViaPoolServer_thenSessionIsValid to ECALoginTests — verifies that a plain ECA JWT login through the pool server produces a valid session (non-DPoP path)
• Fixes an accidental ?? false default on forceAdvancedAuthentication in BaseAuthFlowTester.launchLoginAndValidate that would suppress the flag when nil was intentionally passed

Note: This commit should have been included in #4130. Opening as a separate PR to avoid rebasing the already-reviewed branch.

Test plan

• AuthFlowTester: test_givenNoDPoP_whenLoginViaPoolServer_thenSessionIsValid passes against login.test1.pc-rnd.salesforce.com

[github-actions]

	Tests	Passed ✅	Skipped	Failed
SalesforceSDKCore iOS ^18 Test Results	979 ran	979 ✅

Test	Result
No test annotations available

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.30%. Comparing base (babb82c) to head (bb90ddc).

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #4140      +/-   ##
==========================================
- Coverage   71.62%   71.30%   -0.33%     
==========================================
  Files         254      254              
  Lines       22697    22687      -10     
==========================================
- Hits        16256    16176      -80     
- Misses       6441     6511      +70     

Components	Coverage Δ
Analytics	70.78% <ø> (ø)
Common	70.88% <ø> (-0.10%)	⬇️
Core	66.85% <ø> (-0.46%)	⬇️
SmartStore	73.41% <ø> (-0.05%)	⬇️
MobileSync	88.82% <ø> (-0.02%)	⬇️
see 12 files with indirect coverage changes

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[github-actions]

	Tests	Passed ☑️	Skipped ⚠️	Failed ❌️
AuthFlowTester UI Test Results all	109 ran	62 ✅	5 ⚠️	42 ❌

Test	Result
AuthFlowTester UI Test Results all
AuthFlowTesterUITests.xctest
LegacyLoginTestsNotHybrid.testCAOpaque_AllScopes_WebServerFlow()	❌ failure
LegacyLoginTestsNotHybrid.testCAOpaque_AllScopes_WebServerFlow_InAppWebView()	❌ failure
LegacyLoginTestsNotHybrid.testCAOpaque_DefaultScopes_WebServerFlow_InAppWebView()	❌ failure
MultiUserLoginTests.testAdvancedAuthUser_HasBWFlag_RegularAuthUser_DoesNot()	❌ failure
MultiUserLoginTests.testLogoutUserWithDynamicConfig_OtherUserUnaffected()	❌ failure
MultiUserLoginTests.testDifferentAppTypes_RevokeAccessForCaUser_EcaUserUnaffected()	❌ failure
MultiUserLoginTests.testFlagDiversity_NonHybridOpaqueVsHybridJwt()	❌ failure
MultiUserLoginTests.testBeaconAndNonBeacon_MultiUser()	❌ failure
MultiUserLoginTests.testBothStatic_SameApp_DifferentScopes()	❌ failure
MultiUserLoginTests.testBothStatic_DifferentApps()	❌ failure
MultiUserLoginTests.testFlagDiversity_BeaconNonHybridJwtVsHybridOpaque()	❌ failure
ECALoginTests.testDynamicConfigurationWithInvalidScope()	❌ failure
RefreshTokenMigrationTests.testFlagDiversity_MigratedBeaconJwtVsNonHybridOpaque()	❌ failure
RefreshTokenMigrationTests.testMigrateBeaconOpaqueToJWTAndBack()	❌ failure
RefreshTokenMigrationTests.testMigrateCAToBeaconAndBack()	❌ failure
RefreshTokenMigrationTests.testMigrateCAToBeacon()	❌ failure
RefreshTokenMigrationTests.testMigrateCAUserAgentToBeaconWebServer()	❌ failure
RefreshTokenMigrationTests.testMigrateOneUserOnly()	❌ failure
RefreshTokenMigrationTests.testMigrateBeacon_AddMoreScopes()	❌ failure
RefreshTokenMigrationTests.testMigrateBeaconToCA()	❌ failure
RefreshTokenMigrationTests.testMigrateCAToECA()	❌ failure
WelcomeLoginTests.testWelcomeDiscovery_AdvancedAuthLoginHost()	❌ failure
WelcomeLoginTests.testWelcomeDiscovery_AdvancedAuthLoginHost_DynamicConfig()	❌ failure
LoginWithRestartTests.testBeaconJwt_SubsetScopes_DynamicConfiguration_WithRestart()	❌ failure
LoginWithRestartTests.testBeaconJwt_DefaultScopes_DynamicConfiguration_WithRestart()	❌ failure
LoginWithRestartTests.testBeaconOpaque_DefaultScopes_WithRestart()	❌ failure
LoginWithRestartTests.testAdvancedAuth_WithRestart()	❌ failure
BeaconLoginTests.testBeaconOpaque_DefaultScopes()	❌ failure
BeaconLoginTests.testBeaconJwt_DefaultScopes()	❌ failure
BeaconLoginTests.testBeaconOpaque_AllScopes()	❌ failure
BeaconLoginTests.testBeaconJwt_AllScopes()	❌ failure
BeaconLoginTests.testBeaconOpaque_SubsetScopes()	❌ failure
BeaconLoginTests.testBeaconJwt_SubsetScopes()	❌ failure
AdvancedAuthBeaconLoginTests.testBeaconJwt_AllScopes()	❌ failure
AdvancedAuthBeaconLoginTests.testBeaconJwt_DefaultScopes()	❌ failure
AdvancedAuthBeaconLoginTests.testBeaconOpaque_DefaultScopes()	❌ failure
AdvancedAuthBeaconLoginTests.testBeaconJwt_SubsetScopes()	❌ failure
AdvancedAuthBeaconLoginTests.testBeaconOpaque_SubsetScopes()	❌ failure
AdvancedAuthBeaconLoginTests.testBeaconOpaque_AllScopes()	❌ failure
RefreshTokenMigrationWithRestartTests.testMigrateCAToBeacon_WithRestart()	❌ failure
RefreshTokenMigrationWithRestartTests.testMigrateBeaconScopeAddition_WithRestart()	❌ failure
RefreshTokenMigrationWithRestartTests.testMigrateMultipleUsers_WithRestart()	❌ failure

[sfdctaka]

LGTM!