Scale filter does not correctly deserialize `size` property

[matthew-carroll]

The ScaleFilter current serializes its size property using string interpolation, which sends "[Size]" to FFMPEG. Update the filter to serialize the appropriate string representation of a size to FFMPEG.

[abhay-s-rawat]

Working on it, I have fixed at my end, soon will send a pull request to owner.

[Thomasssb1]

Fixed in my new PR #9

[matthew-carroll]

The referenced PR was merged, but I can't tell if this problem was solved. Re-visit this issue and see if it really is resolved.

[Thomasssb1]

Currently looking into this, but I am wondering what the use case is for VideoSize over just height and width? You mentioned you use it in your own project & would like to know so I can fix appropriately.

[matthew-carroll]

@Thomasssb1 I don't remember the context of this, but I'm guessing that I use VideoSize to pass around both a width and a height. Similar to the reason that we have Size in Flutter.