Address Copilot review feedback

- Skip prefixing for external URLs (http/https/protocol-relative/data:)
- Use IsNullOrWhiteSpace for AppBasePath check to align with PR #22514

framework/src/Volo.Abp.AspNetCore.Components.Web.Theming/Bundling/ComponentBundleUrlBuilder.cs

@@ -14,11 +14,16 @@ public class ComponentBundleUrlBuilder : IComponentBundleUrlBuilder, ITransientD
     {
         Check.NotNull(fileName, nameof(fileName));
 
-        var pathBase = !string.IsNullOrEmpty(appBasePath)
+        if (IsExternalUrl(fileName))
+        {
+            return Task.FromResult(fileName);
+        }
+
+        var pathBase = !string.IsNullOrWhiteSpace(appBasePath)
             ? appBasePath
             : ExtractPathBaseFromNavigationBaseUri(navigationBaseUri);
 
-        if (string.IsNullOrEmpty(pathBase))
+        if (string.IsNullOrWhiteSpace(pathBase))
         {
             return Task.FromResult(fileName);
         }
@@ -32,9 +37,15 @@ public class ComponentBundleUrlBuilder : IComponentBundleUrlBuilder, ITransientD
         return Task.FromResult(normalized + fileName.RemovePreFix("/"));
     }
 
+    protected virtual bool IsExternalUrl([NotNull] string fileName)
+    {
+        return fileName.StartsWith("//", StringComparison.Ordinal) ||
+               (fileName.Contains(':') && Uri.TryCreate(fileName, UriKind.Absolute, out _));
+    }
+
     protected virtual string? ExtractPathBaseFromNavigationBaseUri([CanBeNull] string? navigationBaseUri)
     {
-        if (string.IsNullOrEmpty(navigationBaseUri))
+        if (string.IsNullOrWhiteSpace(navigationBaseUri))
         {
             return null;
         }

framework/test/Volo.Abp.AspNetCore.Components.Web.Theming.Tests/Volo/Abp/AspNetCore/Components/Web/Theming/Bundling/ComponentBundleUrlBuilder_Tests.cs

@@ -84,4 +84,22 @@ public class ComponentBundleUrlBuilder_Tests
         await Should.ThrowAsync<System.ArgumentNullException>(async () =>
             await _builder.BuildAsync(null!, appBasePath: "/foo", navigationBaseUri: null));
     }
+
+    [Theory]
+    [InlineData("https://cdn.example.com/foo.css")]
+    [InlineData("http://cdn.example.com/foo.css")]
+    [InlineData("//cdn.example.com/foo.css")]
+    [InlineData("data:text/css;base64,Zm9vIA==")]
+    public async Task Should_Not_Prefix_External_Urls(string externalUrl)
+    {
+        (await _builder.BuildAsync(externalUrl, appBasePath: "/foo", navigationBaseUri: "https://localhost/foo/"))
+            .ShouldBe(externalUrl);
+    }
+
+    [Fact]
+    public async Task Should_Treat_Whitespace_AppBasePath_As_Not_Provided()
+    {
+        (await _builder.BuildAsync("/__bundles/Global.css", appBasePath: "   ", navigationBaseUri: "https://localhost/foo/"))
+            .ShouldBe("/foo/__bundles/Global.css");
+    }
 }