Quote Block: Unneeded left padding when block is centred

[laurelfulford]

Describe the bug

The left padding that's applied to the quote block isn't removed when the block is centred, even though it no longer has a left border.

This is related to changes from #13248; I noticed it while testing the corresponding Core patch in Twenty Nineteen, 46239.

It's important to note this isn't really visually noticeable, at least in my testing, but should probably be fixed for consistency.

To Reproduce
Steps to reproduce the behavior:

1. Start with a theme that includes support wp-block-styles, and doesn't override the left and right padding on the quote block. Twenty Nineteen with the patch on this ticket is one candidate (though I realize that's a fiddly one to test with! I'll circle back if I find a better example).
2. Add a quote block.
3. Align the text centre.

Expected behavior
That the text would be centred, with no left padding.

Screenshots

Front end:

Editor: