fix(button): fixed loading button form variant alignment

[ArtBlue]

Fixes #1940

• This PR contains CSS changes
• This PR does not contain CSS changes

Description

Fixes the center alignment of loading button.

Screenshots

BEFORE

AFTER

Checklist

• I verify the build is in a non-broken state
• I verify all changes are within scope of the linked issue

• I regenerated all CSS files under dist folder
• I tested the UI in all supported browsers
• I did a visual regression check of the components impacted by doing a Percy build and approved the build
• I tested the UI in dark mode and RTL mode
• I added/updated/removed Storybook coverage as appropriate

[LuLaValva]

Looks good!

I'll approve, but would like to know— there aren't any designs in Figma that suggest this now, if there is potential for more centered graphics like this in the future it might make sense to add a class for them so we don't duplicate all of this logic.

[ArtBlue]

Looks good!

I'll approve, but would like to know— there aren't any designs in Figma that suggest this now, if there is potential for more centered graphics like this in the future it might make sense to add a class for them so we don't duplicate all of this logic.

Possibly, but it's hard to anticipate that sort of thing. Also, requiring any sort of modifier for centering would be a breaking change.

[LuLaValva]

Also, requiring any sort of modifier for centering would be a breaking change.

Oh, right. Yes, definitely leave it as it is then.