Date Time Picker Custom Date Format Does Not Preserve Escape Characters When Imported via "Import Field Groups" Tool

ACF version: 5.12.2 (also tested on 5.10.2)
WordPress version: 5.9.3 (also tested on 5.8.3)

Repo steps:

1. Create a Date Time Picker field
2. Use a custom date format that includes escaped characters (i.e. Y-m-d\TH:i:s\Z to add literal T in the middle and Z at the end)
3. Export the field
4. Import via the "Import Field Groups" tool

Result:
The escape characters (\) are not preserved. The resulting import would have the custom date format Y-m-dTH:i:sZ. The escape slashes have to be manually re-inserted.

Expected:
The escape characters should be preserved during the import.

Start by reproducing the issue with the Date Time Picker and the "Import Field Groups" tool using the custom format Y-m-d\TH:i:s\Z. Trace the import handling for the exported field format and verify that the imported value preserves both escape characters; done means the format remains unchanged after import.