Wedding date not persistent

[ChurchCRMBugReport]

This is more a less a duplicate of issue #4574

When entering a wedding date on the family record the wedding date is not persistent (saved)

During the initial report (#4574) my expectation was the issue could be related to the Dutch translation. On the dev environment (US English locale) the exact same problem occurs.

Collected Value Title	Data
Page Name	/churchcrm/FamilyView.php
Screen Size	900x1440
Window Size	737x1423
Page Size	1208x1423
Platform Information	Linux churchcrmdev 4.4.0-1073-aws #83-Ubuntu SMP Sat Nov 17 00:26:27 UTC 2018 x86_64
PHP Version	7.1.20
SQL Version	5.6.39.0
ChurchCRM Version	3.1.2
Reporting Browser	Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36
Prerequisite Status	All Prerequisites met
Integrity check status	{"status":"success"}

[crossan007]

I can reproduce this on the demo.churchcrm.io

Begin with a family without a wedding date.
Use the date picker to select a wedding date (note that the datepicker supplies DD-MM-YYYY)
Click Save
Notice that the family edit page for the same family loads again.
Note that the date format is now YYYY-MM-DD
Click save again
Notice that the date is now saved and visible on the family view page.

If you click cancel; or navigate away from the second load of the family edit page, then the wedding date is not persisted to the database.

[DawoudIO]

Just checked the date picker is now using 2020-11-17 so this must have been fixed a while back.