[Cashtab] [Extension] [Code cleanup p5 retry] Update comments and function name for triggerApprovalModal

Summary:
T2751

Depends on D12546

Rename function and clean up comments

Test Plan:
npm run extension
Update your local extension build and ensure that it is the only active cashtab extension
go to components.cashtab.com
confirm address sharing still works

Reviewers: #bitcoin_abc, kieran709

Reviewed By: #bitcoin_abc, kieran709

Differential Revision: https://reviews.bitcoinabc.org/D12547