fix: Video.jump_to() fails with negative indexes (#4294)

* support negative indexes in Video.jump_to()

* deprecate `Video.jump_to_async()` and `seek_async()`` methods

sdk/python/packages/flet/src/flet/core/video.py

@@ -265,15 +265,31 @@ async def previous_async(self):
     def seek(self, position_milliseconds: int):
         self.invoke_method("seek", {"position": str(position_milliseconds)})
 
+    @deprecated(
+        reason="Use seek() method instead.",
+        version="0.25.0",
+        delete_version="0.28.0",
+    )
     async def seek_async(self, position_milliseconds: int):
         await self.invoke_method_async("seek", {"position": str(position_milliseconds)})
 
     def jump_to(self, media_index: int):
-        assert self.__playlist[media_index], "index out of range"
+        assert self.__playlist[media_index], "media_index is out of range"
+        if media_index < 0:
+            # dart doesn't support negative indexes
+            media_index = len(self.__playlist) + media_index
         self.invoke_method("jump_to", {"media_index": str(media_index)})
 
+    @deprecated(
+        reason="Use jump_to() method instead.",
+        version="0.25.0",
+        delete_version="0.28.0",
+    )
     async def jump_to_async(self, media_index: int):
-        assert self.__playlist[media_index], "index out of range"
+        assert self.__playlist[media_index], "media_index is out of range"
+        if media_index < 0:
+            # dart doesn't support negative indexes
+            media_index = len(self.__playlist) + media_index
         await self.invoke_method_async("jump_to", {"media_index": str(media_index)})
 
     def playlist_add(self, media: VideoMedia):