Fix iOS keychain config for MSAL token persistence

Align iOS keychain-access-groups entitlement with Mac Catalyst to use
com.microsoft.adalcache (MSAL's default shared keychain group). Add
WithIosKeychainSecurityGroup to the MSAL builder for iOS and Mac
Catalyst so tokens persist correctly across app restarts.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mattleibow

10.0/MauiBlazorWebEntra/MauiBlazorWebEntra/Platforms/iOS/Entitlements.plist

@@ -4,7 +4,7 @@
     <dict>
         <key>keychain-access-groups</key>
         <array>
-            <string>$(AppIdentifierPrefix)$(CFBundleIdentifier)</string>
+            <string>$(AppIdentifierPrefix)com.microsoft.adalcache</string>
         </array>
     </dict>
 </plist>

10.0/MauiBlazorWebEntra/MauiBlazorWebEntra/Services/MsalServiceExtensions.cs

@@ -15,7 +15,11 @@ public static IServiceCollection AddMsalClient(this IServiceCollection services)
         var msalBuilder = PublicClientApplicationBuilder
             .Create(MsalConfig.ClientId)
             .WithAuthority(MsalConfig.Authority)
-            .WithRedirectUri(MsalConfig.RedirectUri);
+            .WithRedirectUri(MsalConfig.RedirectUri)
+#if IOS || MACCATALYST
+            .WithIosKeychainSecurityGroup("com.microsoft.adalcache")
+#endif
+            ;
 
 #if WINDOWS
         // Windows: use embedded WebView2 browser + WAM broker for authentication.