Submit button styles break theme styles

Hi

The inline css styles on button borders are breaking theme editor styles.

https://github.com/Automattic/jetpack/blob/5ddf14cdaf5b45f3e4e05e1c4c96bb72f3556c46/extensions/shared/submit-button.js#L91

You can see an example in the image below:

Can we remove this rule? It seems very specific and the only way I can see to fix it is to use _!important_ rules, which could have issues with custom colours elsewhere.

Start in extensions/shared/submit-button.js at line 91 and inspect the inline CSS applied to the button borders. Remove the rule that overrides theme editor styles, then verify that theme button styling is no longer broken without relying on !important rules.

Written by the indexing model from the issue text.