JS response handler no longer executes on background thread.
JS response handler no longer executes on background thread.

Due to JS now being limited to main thread, all sync dispatches are handled on the main thread as well.

Allow2CEO/browser-ios,Allow2CEO/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,brave/browser-ios,brave/browser-ios,brave/browser-ios,brave/browser-ios,brave/browser-ios,Allow2CEO/browser-ios,brave/browser-ios