Add animated loading icon on publish button

[istarkov]

Description

Add animated loading icon on publish button

ref #1715

Todo:

• - https://discord.com/channels/955905230107738152/1117940560574021782

Errors are now aligned

Steps for reproduction

1. click button
2. expect xyz

Code Review

• hi @kof, I need you to do
  • conceptual review (architecture, feature-correctness)
  • detailed review (read every line)
  • test it on preview

Before requesting a review

• made a self-review
• added inline comments where things may be not obvious (the "why", not "what")

Before merging

• tested locally and on preview environment (preview dev login: 5de6)
• updated test cases document
• added tests
• if any new env variables are added, added them to .env.example and the builder/env-check.js if mandatory

[vercel]

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Name	Status	Preview	Updated (UTC)
webstudio-builder	✅ Ready (Inspect)	Visit Preview	Jun 15, 2023 9:24pm

[kof]

@taylornowotny we need to update the design system in figma with having an animated loading svg in the button in the pending state, this is what it looks like right now https://share.descript.com/view/PEa9POv1WUq

I already talked to @markxtang that we need to improve the svg, but that's not the issue here, what we need is a state in figma for the button that is called "pending" and is using the animated svg and works with other states