TextureSlicer should avoid squishing 9slice corners

## What problem does this solve or what need does it fill?

context: Using a free asset from unity (https://assetstore.unity.com/packages/2d/gui/icons/2d-casual-ui-hd-82080#content), it contains the following image which I can 9slice:

if I load it in bevy, and set a smaller length, I get this behaviour:

## What solution would you like?

Maybe an added "minimum scale" for its corners ?

## Workaround

Of course, an ideal asset would be more mininal if its objective is to 9scale it, like:

Which results in a better behaviour (ideally aligning perfectly but here my assets are to blame.)