Add GA Event tracking for Add and Edit Supporter Wall links in TwG settings

[wpdarren]

Bug Description

While going through the GA event tickets for Thank with Google, I noticed that we were not tracking when a user clicks on the Add supporter wall and Edit supporter wall widget links within TwG settings. All of the other settings have an event, but these links don't. We are also tracking the link when a user clicks on the CTA button to add a widget on the Supporter Wall notification banner, so it makes sense to track these links too.

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