docs(uploads): update deleteFile and deleteImage methods

This commit updates the `deleteFile` and `deleteImage` methods in `FeedsClient` and `FeedsClientImpl` to accept the `url` parameter as a named, required argument.

Additionally, it adds a new code snippet to the documentation demonstrating how to use these methods to delete files and images from the CDN.

Author: xsahil03x

docs_code_snippets/03_03_file_uploads.dart

@@ -2,6 +2,7 @@
 
 import 'package:stream_feeds/stream_feeds.dart';
 
+late StreamFeedsClient client;
 late Feed feed;
 late Activity activity;
 late StreamAttachmentUploader attachmentUploader;
@@ -79,6 +80,14 @@ Future<void> howToUploadAFileOrImageStep4() async {
   );
 }
 
+Future<void> howToDeleteAFileOrImage() async {
+  // Delete an image from the CDN
+  await client.deleteImage(url: 'https://mycdn.com/image.png');
+
+  // Delete a file from the CDN
+  await client.deleteFile(url: 'https://mycdn.com/file.pdf');
+}
+
 // Your custom implementation of CdnClient
 class CustomCDN implements CdnClient {
   @override

packages/stream_feeds/lib/src/client/feeds_client_impl.dart

@@ -294,7 +294,7 @@ class StreamFeedsClientImpl implements StreamFeedsClient {
   @override
   Activity activity({
     required String activityId,
-    required FeedId fid, 
+    required FeedId fid,
     ActivityData? initialData,
   }) {
     return Activity(
@@ -442,8 +442,12 @@ class StreamFeedsClientImpl implements StreamFeedsClient {
   }
 
   @override
-  Future<Result<void>> deleteFile(String url) => _cdnClient.deleteFile(url);
+  Future<Result<void>> deleteFile({required String url}) {
+    return _cdnClient.deleteFile(url);
+  }
 
   @override
-  Future<Result<void>> deleteImage(String url) => _cdnClient.deleteImage(url);
+  Future<Result<void>> deleteImage({required String url}) {
+    return _cdnClient.deleteImage(url);
+  }
 }

packages/stream_feeds/lib/src/feeds_client.dart

@@ -667,7 +667,7 @@ abstract interface class StreamFeedsClient {
   /// ```
   ///
   /// Returns a [Result] indicating success or failure of the deletion operation.
-  Future<Result<void>> deleteFile(String url);
+  Future<Result<void>> deleteFile({required String url});
 
   /// Deletes a previously uploaded image from the CDN.
   ///
@@ -689,7 +689,7 @@ abstract interface class StreamFeedsClient {
   /// ```
   ///
   /// Returns a [Result] indicating success or failure of the deletion operation.
-  Future<Result<void>> deleteImage(String url);
+  Future<Result<void>> deleteImage({required String url});
 
   /// The moderation client for managing moderation-related operations.
   ///