Enable page feedback even without a Google analytics ID

[chalin]

• Contributes to Release 0.8.0 preparation #1667
• Contributes to Page feedback: support for Google Analytics 4 (GA4) #1302
• Fixes Page feedback shouldn't require that a Google Analytics ID be set as a config parameter #1311
• Refactors the feedback.html partial and its point of use so that testing whether the feature is enabled happens inside the partial
• Adds an entry to the ChangeLog
• Updates the Feedback section of the docs, and adds a version note.

Preview, e.g.: https://deploy-preview-1727--docsydocs.netlify.app/docs/adding-content/feedback/#setup-1 -- navigate to the end of the page to see the feedback form

There are no non-whitespace changes to the generated user guide except for the changes made to the User Feedback section:

$ (cd public && git diff -bw --ignore-blank-lines -- . ':(exclude)*/_print/*' ':(exclude)*.xml') | grep ^diff
diff --git a/docs/adding-content/feedback/index.html b/docs/adding-content/feedback/index.html

[geriom]

Thank you! LGTM