Remove the IIFE's from files starting with E

This MR only remove unnecessary IIFEs.

Affected files

• app/assets/javascripts/boards/components/modal/empty_state.js
• app/assets/javascripts/issuable/time_tracking/components/estimate_only_pane.js
• app/assets/javascripts/u2f/error.js
• spec/javascripts/environments/environments_store_spec.js

ref: #29219 (moved)

changed title from Remove IIFEs to Remove the IIFE's from files starting with E

closed