[HCA DX] Track clicks on "Export" button

[MillenniumFalconMechanic]

Need

We need to add tracking of the cohort export button to monitor user interactions and optimize conversions. This tracking will allow us to analyze the conversion funnel more accurately, ensuring that the export button is performing as expected.

Approach

• Add a button-cohort-export ID to the cohort export button. (See https://github.com/DataBiosphere/findable-ui/issues/218.)
• Use GTM's built-in click variables to enable click tracking.
• Create trigger that fires on "Click - All Elements" / "Some Clicks" to target only the export button.

Definition of Done

Clicks on export data button are accessible in the query explorer for both prod and staging:

• [x] data.humancellatlas.org - GA4
• [x] data.humancellatlas.dev.clevercanary.com - GA4

[jpaten]

@MillenniumFalconMechanic Seems to be working!

Prod:

Staging: