Add missing semicolon to the gtag call

[tomalec]

Changes proposed in this Pull Request:

Add the missing semicolon to the gtag call, allowing the HTML to be minified.
Fixes https://wordpress.org/support/topic/gtag-event-js-error/

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:

1. Configure the extension to use gtag implementation
2. Open the shop page with list of products as non-admin user (incognito)
3. Check the source code of the page
   gtag('event', 'view_item_list',… should have ; at the end of line.

Additional details:

Changelog entry

Fix - Add semicolon after gtag calls.

[martynmjones]

Hey @tomalec, thanks for the fix!

Tested locally and confirmed that all calls to gtag( 'event'... end with a semi-colon so LGTM ✅