Flatpickr only use language and not locale

[jibees]

What? Why?

Flatpickr can be configured by passing a locale but it's more only a language than a locale.
Create and use a small attribute onto I18n javascript object.

Closes #7928

What should we test?

1. Set up a locale like fr_CA
2. Login as admin and choose French on the homepage
3. Visit admin/orders/bulk_management
4. Open the console and notice there is no error, and the date(time)picker is well configured in fr language

Release notes

Use the right language for date(time)picker when configured locale contains also country

Changelog Category: User facing changes

[codecov]

Codecov Report

Merging #7972 (6d04c99) into master (c9159a3) will decrease coverage by 70.13%.
The diff coverage is n/a.

❗ Current head 6d04c99 differs from pull request most recent head f39cc49. Consider uploading reports for the commit f39cc49 to get more accurate results

@@             Coverage Diff             @@
##           master    #7972       +/-   ##
===========================================
- Coverage   93.27%   23.13%   -70.14%     
===========================================
  Files         640      568       -72     
  Lines       18152    20869     +2717     
===========================================
- Hits        16931     4829    -12102     
- Misses       1221    16040    +14819     

Impacted Files	Coverage Δ
app/jobs/job_logger.rb	0.00% <0.00%> (-100.00%)	⬇️
app/jobs/heartbeat_job.rb	0.00% <0.00%> (-100.00%)	⬇️
app/services/unit_price.rb	0.00% <0.00%> (-100.00%)	⬇️
app/models/order_balance.rb	0.00% <0.00%> (-100.00%)	⬇️
app/helpers/mailer_helper.rb	0.00% <0.00%> (-100.00%)	⬇️
app/jobs/bulk_invoice_job.rb	0.00% <0.00%> (-100.00%)	⬇️
app/services/cap_quantity.rb	0.00% <0.00%> (-100.00%)	⬇️
app/services/cart_service.rb	0.00% <0.00%> (-100.00%)	⬇️
app/services/order_syncer.rb	0.00% <0.00%> (-100.00%)	⬇️
app/models/coordinator_fee.rb	0.00% <0.00%> (-100.00%)	⬇️
... and 563 more

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[Matt-Yorkley]

👌

[filipefurtad0]

Hey @jibees ,
Nice!

Before - console errors; translation on the date-time-picker is broken (for fr_CA):

After - no console errors; translation on the date-picker is working!

Checked the following pages:

• bulk order management (above)
• orders page
• (some) reports

Also staged and tested in servers in which the locale is fr (regression test):

• checked the same pages as above - all good 👍

Awesome - ready to go 🎉