Bug 1987158 - Capture url/referrer/title with recordElementClick()

[caugner]

1. Adds url, referrer, and title to the element_click event.
2. Automatically captures these as part of recordElementClick().

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1987158.

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[caugner]

@travis79 Any tips how to test this? There don't seem to be tests for the page_load event, presumably because it's not straight-forward to mock?