Page Properties dialog instrumented twice

[HitmanInWis]

JavaScript executing on Page Properties instruments the dialog twice. I'm unsure why, but the dialog-loaded event seems to trigger twice on open of Page Properties, hence double-instrumenting.

This impacts the following:

• Inherited fields (Brand Slug) - apps/core/wcm/components/page/v3/page/clientlibs/editor/js/brandSlugTuple.js
• Page Image upload field - apps/core/wcm/components/image/v3/image/clientlibs/editor/js/image.js

Perhaps we need a simple mechanism that marks a dialog as "instrumented" so that if dialog-loaded fires multiple times for the same dialog open we can exit quickly on instances after the first load.