fix/exportProjectAsZip

[adityagarg06]

Fixes #2311

Changes:
Removed the exportProjectAsZip function and directly link to the download URL.

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• 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

[lindapaiste]

Thank you! I can confirm that this works and that it fixes the issue so it's good to merge but I do have some further thoughts.

Initially when I mentioned using an <a> tag I was thinking about replacing the <button> itself with the <a>. However that caused styling issues. This approach with the hidden <a> tag avoids those issues so that's great. 👍

We also have export logic in the Nav component for exporting the current sketch from the editor screen. So now I'm wondering if it may be better to move your logic into a utility function which can be used in both places.