Subscription filter values displays technical values for date, which can be difficult to read for humans

[flamber]

Describe the bug Subscription filter values displays technical values for date, which can be difficult to read for humans

To Reproduce

1. Dashboard > add a question and connect a couple of date filters with default values
2. Send subscription - the email received will look like this

Expected behavior Since emails are static by nature, it would be great if we showed the static period (just like the relative filter preview does), but any less technical way of showing dates would be helpful. It should fall-back to the technical value if it cannot translate instead of displaying nothing/null/error.

Information about your Metabase Installation: Tested 0.44.0