add user locale field to mobile app user settings table + change going on call push notification text

[joeyorlando]

What this PR does

• add user locale field to mobile app user settings table + add a test that sends PATCH requests to this endpoint
• change "you're going on call" push notification text to include localized shift time. The general format is now:

  f"You're going on call in {time_until_going_oncall} for schedule {schedule.name}, {formatted_shift}"

  • time_until_going_oncall is a "human-readable" format of the time until the start)
  • schedule.name is self-explanatory
  • formatted_shift this depends on the shift. If the shift starts and ends on the same day, the format will be "HH:mm - HH:mm". Otherwise, if the shift starts and ends on different days, the format will be "YYYY-MM-DD HH:mm - YYYY-MM-DD HH:mm". Note that all datetime related formatting will use the new locale field that we are now storing in the mobile app user settings table. If no locale is yet present we will fallback to "en"

Which issue(s) this PR fixes

closes #2024
https://github.com/grafana/oncall-mobile-app/issues/187

Checklist

• Unit, integration, and e2e (if applicable) tests updated
• Documentation added (or pr:no public docs PR label added if not required)
• CHANGELOG.md updated (or pr:no changelog PR label added if not required)

[vstpme]

09 h 00 looks a bit weird IMO, maybe it should be 09:00 or at least 09h00?
I'm not an expert in locales, but I can't see anything similar to this format in the reference for fr-CA.

[vstpme]

why use code \u20 instead of regular " " spaces?

[joeyorlando]

@vadimkerr good questions 👍 I agree with your points. I'll need to see if I can configure the babel package to modify these behaviours.

[joeyorlando]

@vadimkerr these two points you raised seem to be coming from the babel library itself. I've raised two questions over in that repo to clarify this behaviour.

\u202f character
python-babel/babel#1012
We could do a string replacement on this character, but that seems flaky imo.

Odd spacing in time formatting w/ fr_CA locale
python-babel/babel#1013

It appears like this is the default formatting behaviour for fr_CA?

>>> babel.dates.format_time(now, format="short", locale="fr_CA")
'15 h 27'
>>> babel.dates.format_time(now, format="short", locale="fr")
'15:27'
>>> babel.dates.format_time(now, format="short", locale="en")
'3:27\u202fPM'

I don't think overriding the datetime formatting pattern syntax would be useful here, because that would default the purpose of localizing the datetimes in the first place 😕

[joeyorlando]

@vadimkerr these formatting decisions seem to be the default coming from Unicode CLDR. I suggest for now we stick with these and refine them over time if need be. Overriding them to handle different formats/locales, to suit our liking, seems like a lot of work.

Regarding the \u202f unicode characters that babel returns. I verified that Android renders these properly, I presume iOS does as well. For example, when 6/13/23, 10:00\u202fPM - 6/14/23, 10:00\u202fPM is sent to FCM as the notification title: