As discussed in https://hackmd.io/33M5Wb-JT7-0fneA0JuHPA `SourceMessage`
strings are not sufficient for matching translations.
This commit updates `@angular/localize` to use `MessageId`s for translation
matching instead.
Also the run-time translation will now log a warning to the console if a
translation is missing.
BREAKING CHANGE:
Translations (loaded via the `loadTranslations()` function) must now use
`MessageId` for the translation key rather than the previous `SourceMessage`
string.
PR Close#32594