Fix missing space between sketch name and author in embed view

[Nixxx19]

Issue:

Fixes #4040

Demo:

Before:

After:

Changes:

• Added horizontal margin to .toolbar__project-owner in _toolbar.scss to create spacing between the sketch name, "by" text, and the author link.

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• has no typecheck errors (npm run typecheck)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123
• meets the standards outlined in the accessibility guidelines

[raclim]

This looks great, thanks so much!