Wrap inline remove_from_cart script in IIFE

[tomalec]

Changes proposed in this Pull Request:

Wrap inline remove_from_cart script in IIFE
To avoid syntax errors for const re-declaration.
Quick fix for https://wordpress.org/support/topic/javascript-output-twice/#post-17098290
7098382-zd-a8c

This is a regression from #283

Checks:

• Does your code follow the WordPress coding standards?
• Have you written new tests for your changes, as applicable?
• Have you successfully run tests with your changes locally?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Screenshots:

Detailed test instructions:

Global

1. Enable cart tracking in /wp-admin/admin.php?page=wc-settings&tab=integration&section=google_analytics
2. Open the shop page not as admin
3. Add something to the cart
4. Open cart page
5. Open the browser console
6. Check that there is no selector global variable.

Duplicate exectuion

1. Enable cart tracking in /wp-admin/admin.php?page=wc-settings&tab=integration&section=google_analytics
2. Add mini-cart widget to the cart page
3. Open the shop page not as admin
4. Add something to the cart
5. Open cart page
6. Open the browser console
7. Check that there is no syntax errors

Additional details:

1. I think we can actually move that script to the external shared file, but I'd leave it for future improvement and ship a quick fix sooner than later.

Changelog entry

Fix - JS syntax error on pages with cart and mini-cart rendered, which was causing purchases and cart removals not to be tracked.

[martynmjones]

Hey @tomalec, thanks for the quick fix!

Tested locally and confirmed that this change resolves the syntax warning so LGTM ✅