MPP-2758: Fix email wrapper to display tracker report link correctly

[rafeerahman]

This PR fixes MPP-2758.

Bug description

The tracker report link in forwarded emails were not showing up as a hyperlink.

This is because of an incorrect condition comparing the tracker removal string, instead of the integer value of the number of trackers removed.

Screenshot of fix

Now it is displayed as a hyperlink.

How to test

• Go to /emails/wrapped_email_test?language=en&has_premium=Yes&has_tracker_report_link=Yes&num_level_one_email_trackers_removed=1 in your local env
• Verify that the "X email tracker removed" is clickable and a hyperlink for X > 0.
• For X = 0, verify that it is not clickable.

Checklist (Definition of Done)

• Product Owner accepted the User Story (demo of functionality completed) or waived the privilege.
• Customer Experience team has seen or waived a demo of functionality.
• All acceptance criteria are met.
• Jira ticket has been updated (if needed) to match changes made during the development process.
• I've added or updated relevant docs in the docs/ directory
• Jira ticket has been updated (if needed) with suggestions for QA when this PR is deployed to stage.
• All UI revisions follow the coding standards, and use Protocol tokens where applicable (see /frontend/src/styles/tokens.scss).
• Commits in this PR are minimal and have descriptive commit messages.
• l10n changes have been submitted to the l10n repository, if any.

[jwhitlock]

Thanks @rafeerahman, this look like it has been broken since I changed this code last September. I've added a test that would have detected this bug.