This PR fixes two bugs:
- Fixes#40419
- Fixes#41393
The first is when the aspect ratio of the `width` and `height` does not
match the aspect ratio of the `blurDataURL` provided. This can result in
artifacts around the edges. The solution is to add
`preserveAspectRatio="none"`.
The second is when there is no `width` or `height` provided (which is
normal when using `fill`) so the viewBox was undefined. This can also
cause artifacts around the edges. The solution is to change the blur
technique from gaussian to css filter, similar to `next/legacy/image`.
Note: css blur might be [slower in
firefox](https://bugzilla.mozilla.org/show_bug.cgi?id=925025) which is
why we'll only use it for this corner case.
fe762d329f