[video_player] Add poster attribute for html video tag in video_player_platform_interface (flutter#8979)

This PR adds support for the poster attribute on web by introducing a poster field in VideoPlayerWebOptions. It allows setting a thumbnail image for videos using the native HTML5 poster property, improving the out-of-the-box web experience.

This PR is is the changes to platform_interface for this [one](flutter#8940)

Solve this issue:
flutter/flutter#166232

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: Ortes

packages/video_player/video_player_platform_interface/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 6.4.0
 
+* Adds HTML5 video poster support as a VideoPlayerWebOptions.
 * Updates minimum supported SDK version to Flutter 3.27/Dart 3.6.
 
 ## 6.3.0

packages/video_player/video_player_platform_interface/lib/video_player_platform_interface.dart

@@ -429,6 +429,7 @@ class VideoPlayerWebOptions {
     this.controls = const VideoPlayerWebOptionsControls.disabled(),
     this.allowContextMenu = true,
     this.allowRemotePlayback = true,
+    this.poster,
   });
 
   /// Additional settings for how control options are displayed
@@ -439,6 +440,9 @@ class VideoPlayerWebOptions {
 
   /// Whether remote playback is allowed
   final bool allowRemotePlayback;
+
+  /// The URL of the poster image to be displayed before the video starts
+  final Uri? poster;
 }
 
 /// [VideoPlayerWebOptions] can be used to set how control options are displayed

packages/video_player/video_player_platform_interface/pubspec.yaml

@@ -4,7 +4,7 @@ repository: https://github.com/flutter/packages/tree/main/packages/video_player/
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+video_player%22
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 6.3.0
+version: 6.4.0
 
 environment:
   sdk: ^3.6.0

packages/video_player/video_player_platform_interface/test/video_player_web_options_test.dart

@@ -29,4 +29,24 @@ void main() {
       expect(options.allowRemotePlayback, isTrue);
     },
   );
+
+  group('VideoPlayerOptions poster', () {
+    test(
+      'defaults to null',
+      () {
+        const VideoPlayerWebOptions options = VideoPlayerWebOptions();
+        expect(options.poster, null);
+      },
+    );
+
+    test(
+      'with a value',
+      () {
+        final VideoPlayerWebOptions options = VideoPlayerWebOptions(
+          poster: Uri.parse('https://example.com/poster.jpg'),
+        );
+        expect(options.poster, Uri.parse('https://example.com/poster.jpg'));
+      },
+    );
+  });
 }