Enable tracking of urls with tokens in Flexmailer

[artfulrobot]

Overview

Migration of civicrm/org.civicrm.flexmailer#46
See https://lab.civicrm.org/dev/mail/-/issues/81

Before

• Can't track URLs with tokens in CiviMail

After

• Can track URLs with tokens in CiviMail, if you're careful.

[civibot]

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[seamuslee001]

@artfulrobot bunch of style issues mate https://test.civicrm.org/job/CiviCRM-Core-PR/38259/checkstyleResult/new/

[artfulrobot]

test this please

[eileenmcnaughton]

@artfulrobot we chatted about this just now & no-one had concerns about this (although r-run not done yet) other than the documentation / pr explanation side of it - it's hard to tell from the review template what is being changed / what the implications - so if you could amp that out a bit and / or create a docs PR we should be able to get someone to review it & there are no obvious blockers to merging (I didn't quite hear @kcristiano offer to review but his murmur was so encouraging I'm gonna pretend Kevin volunteered.....)

[totten]

@artfulrobot So I've done some r-run, and it is working. Cool. :)

From an r-code perspective, the arrangement around BaseClickTracker::$getTrackerURL feels weird:

• Partially, it sticks out because it's like a parent-method, except written as a static-variable.
• But thinking about it a bit more deeply... the essence of this change is that getTrackerURL($origURL): $trackedURL needs to behave differently. But it feels like the current revision changes everything else in an attempt to reshape things to avoid changing getTrackerURL().

This probably made sense if one initially set out with a goal: Let's patch flexmailer.git and leave civicrm-core.git untouched. But now that they're in the same repo... perhaps it would cleaner to put the getTrackerURLForUrlWithTokens as a private/internal part of the implementation of getTrackerURL() -- as in #19386.

[artfulrobot]

Closing in favour of #19386

(Yes, I had been limiting changes to the extension, not core.)