Remove Google Analytics script loader

[Hathor875]

Remove Google Analytics script loader

Strips the GA script injection from apps/common/Analytics.js. The public API is
retained as no-ops so the existing call sites across the editors keep working;
removing those follows in a separate change.

Refs #82

What changed

• initialize() no longer appends the inline <script> that seeded _gaq and
  pulled in google-analytics.com/ga.js. Both methods are now empty.
• The argument validation went with the injection — there is nothing left to
  validate. Callers that passed a bad type used to get a throw; they now get
  silence, which is the intent: no call site should have to care.
• $('head') was this file's only jQuery dependency, so the module no longer
  touches the DOM or any global beyond window.Common.
• The license header is untouched.

Why the call sites stay

rg -i analytics apps/ --glob '!vendor' returns ~530 hits across the three
editors. Removing them is mechanical, but folding it into this commit would bury
the handful of lines that actually matter behind a diff nobody can review. The
no-op shims keep every one of those call sites working, so this change stands on
its own and cannot break a build. The call-site cleanup lands separately.

The loader was already dead

initialize() is guarded by && false in each editor's Main.js, so ga.js
was never injected in the first place. This commit removes code that had already
stopped running — it is not a behaviour change for users, only a removal of the
dead path and the third-party URL baked into it.

Relation to #85

#85 does this in full — loader, call sites, canAnalytics flags, build config,
HTML loaders (74 files, +12 −781). It is the better end state and stays open;
I will close this if it lands.

It is not mergeable today: open ~2 months, no review, no CI, and main has moved
165 commits since — including Grunt → webpack. It edits build/appforms.json and
build/Gruntfile.js, which no longer exist, so it cannot be rebased. This change
touches one file for that reason, and removes the part that carries the risk.

Testing

• node --check apps/common/Analytics.js — clean.
• Loaded the module in node (global.window = global) and called
  trackEvent() before initialize(), then initialize(), then
  Common.component.Analytics.trackEvent() — no throw, and both aliases still
  resolve to the same object.
• rg "_gaq" apps/ --glob '!vendor' — no matches.
• test/unit-tests/common/index.html (per test(unit-tests): make the harness runnable again #194): 12 passing, unchanged. Note
  the harness has no coverage for this file — rg -i analytics test/ is empty —
  so it confirms no regression elsewhere, not that this file works.