Co-authored-by: Shi Hao Hong <shihaohong94@gmail.com>

Migrate flutter_localizations to null safety.

This reverts commit ae06c19a.

* Regenerate _no.arb and _nb.arb from scratch

* Revert no <--> nb synonym logic

* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

* Sort Localization generation output

- When creating locales that were assumed from existing locales, the
file that is used is non-deterministic. This adds a sort to the iterator
to ensure that the same existing locale is used to generate the assumed
locale
- When generating material, cupertino and date localizations, the generated getters were not sorted. This
introduces an alphabetic sort

* remove main.dart.snapshot

* Refresh .arb files

* Refresh localizations

Revert "Cupertino localization step 12: push translation for all supported languages (#31644)" (#32470)

This reverts commit 10922df6.

Cupertino localization step 8: create a gen_cupertino_localizations and generate one for cupertino english and french (#29824)