Fix interactive tests to use correct app configuration

- Changed Interactive_AADAsync to use GetDefaultUserAsync() instead of GetDefaultUserWithMultiTenantAppAsync()
- Fixed InteractiveConsentPromptAsync to use default app
- Fixed ValidateCcsHeadersForInteractiveAuthCodeFlowAsync to use default app
- Interactive tests should use public client apps, not the multi-tenant confidential app
- This resolves AADSTS7000218 errors (missing client_secret for confidential clients)

Author: RyAuld

tests/Microsoft.Identity.Test.Integration.netcore/SeleniumTests/InteractiveFlowTests.NetFwk.cs

@@ -43,7 +43,7 @@ public void TestInitialize()
         public async Task Interactive_AADAsync()
         {
             // Arrange
-            LabResponse labResponse = await LabUserHelper.GetDefaultUserWithMultiTenantAppAsync().ConfigureAwait(false);
+            LabResponse labResponse = await LabUserHelper.GetDefaultUserAsync().ConfigureAwait(false);
             var result = await RunTestForUserAsync(labResponse).ConfigureAwait(false);
         }
 
@@ -69,7 +69,7 @@ public async Task Interactive_MsaUser_Async()
         [RunOn(TargetFrameworks.NetCore)]
         public async Task InteractiveConsentPromptAsync()
         {
-            var labResponse = await LabUserHelper.GetDefaultUserWithMultiTenantAppAsync().ConfigureAwait(false);
+            var labResponse = await LabUserHelper.GetDefaultUserAsync().ConfigureAwait(false);
 
             await RunPromptTestForUserAsync(labResponse, Prompt.Consent, true).ConfigureAwait(false);
             await RunPromptTestForUserAsync(labResponse, Prompt.Consent, false).ConfigureAwait(false);
@@ -163,7 +163,7 @@ public async Task Interactive_Adfs_DirectAsync()
         [RunOn(TargetFrameworks.NetCore)]
         public async Task ValidateCcsHeadersForInteractiveAuthCodeFlowAsync()
         {
-            LabResponse labResponse = await LabUserHelper.GetDefaultUserWithMultiTenantAppAsync().ConfigureAwait(false);
+            LabResponse labResponse = await LabUserHelper.GetDefaultUserAsync().ConfigureAwait(false);
 
             var pca = PublicClientApplicationBuilder
                .Create(labResponse.App.AppId)