Summary:
Grist recently stopped working on Firefox on iOS. The cause turns out an uncaught error, which is reported as an unhelpful "Script Error", but the act of reporting it causes additional errors, leading to an infinite loop and an unusable browser tab.
Firefox-iOS is to blame, but a workaround is preventing a flood of "Script Error" messages. Specifically, we report only the first of these, and only to the server, suppressing the user-visible toast.
Test Plan: Tested manually on Firefox on iOS. Added a test case, and improve other tests of uncaught errors.
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D3902