Track GA events for the Key Metrics and Audience Segmentation re-show notices

[techanvil]

Feature Description

We need to track GA events for the notices we're displaying when re-showing the Key Metrics and Audience Segmentation widgets to users who had previously hidden them (see #12872 and #12917).

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Acceptance criteria

The following GA events are tracked when their conditions are met:

Event Name	Category	Trigger	Condition
view_notice	{viewContext}-kmw-reshown	element visibility	user views the "Key metrics are back on your dashboard" notice when the Key Metrics widget area is re-shown for an existing user
confirm_notice	{viewContext}-kmw-reshown	click	user clicks "Select metrics" on the "Key metrics are back on your dashboard" notice
dismiss_notice	{viewContext}-kmw-reshown	click	user clicks "Got it" on the "Key metrics are back on your dashboard" notice
view_notice	{viewContext}-audiences-reshown	element visibility	user views the "Visitor groups are back on your dashboard" notice when the Audience Segmentation widget area is re-shown for an existing user
confirm_notice	{viewContext}-audiences-reshown	click	user clicks "Select groups" on the "Visitor groups are back on your dashboard" notice
dismiss_notice	{viewContext}-audiences-reshown	click	user clicks "Got it" on the "Visitor groups are back on your dashboard" notice

Implementation Brief

Test Coverage

QA Brief

Changelog entry