Fix unencoded mailing url query param in Mailing report

[artfulrobot]

Overview

The mailing report generated invalid URLs which broke the report that lists all clicks on a certain tracked link.

Before

The report constructed URLs containing clicked URLs without encoding them, breaking the original URL.

After

Encoding is applied. The report links work.

Comments

Found links where the clicked URL contained a fragment identifier # completely broke the URL generated.

[civibot]

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[seamuslee001]

This seems fine to me merging

[artfulrobot]

Thanks @seamuslee001 for reviewing, merging!