onboarding: one form record activates multiple same onFormSubmit triggers

[andiechu]

Problem

Also it sent multiple Emails to the new memebers too.

Reason

The reason I found that it's because Google App Script's trigger is not that reliable. A lot of people complained about the same question:
https://stackoverflow.com/questions/55283616/script-running-multiple-times-onformsubmit
https://stackoverflow.com/questions/54834837/how-can-i-be-getting-multiple-unwanted-event-blocks-from-the-same-onformsubmit-t/54860085#54860085

Solution

• check again the logic and fix the bug of sending duplicated Emails
• add lock to triggers conditional statement to prevent it from running for multiple times
• refine the logging system