allow default_locale to be set/updated via the addon api

[eviljeff]

split from #18036

We'd like to be able to set during create, and update later, the default locale for the addon's translated strings. This will probably need a lot of validation because it's easy to end up with an add-on with (apparently) entirely missing metadata because those strings aren't present in the newly selected default locale.

[AlexandraMoga]

I'm moving this to the following milestone since we won't push next week.

[ioanarusiczki]

@eviljeff I've been testing on -dev :

• for addons with no translations (for name, summary etc) in their .xpi -> I think for all addon types in this case when default_locale is specified, the create/patch requests work as expected.
• I still have some testing to complete around addons with _locales specified into their .xpis
• I filed Don't return a 200 response when custom_license is not en-US at addon create #19313

[ioanarusiczki]

@eviljeff

I tested various scenarios so I won't detail everything:

• with multiple locales declared in the _locales folder with information about name and summary , at addon create when the JSON also includes information about "name" or "summary" -> it will override the information from the archive -> which is expected

• a value for the default locale is required for ""description", "developer_comments", "homepage", "name", "summary", "support_email" when these are added with a default_locale . -> expected

• when making a PATCH in order to change the default_locale, the name and summary are the mandatory fields. I've noticed that dev hub also requires the "description" (which is an old thing, I am pretty sure but I think it should work the same way as the API)

[eviljeff]

• when making a PATCH in order to change the default_locale, the name and summary are the mandatory fields. I've noticed that dev hub also requires the "description" (which is an old thing, I am pretty sure but I think it should work the same way as the API)

I forget the requirements for devhub - and it's changed a few times over the years. Strictly required metadata to be approved for a listed version is name + summary + license + categories so I used that.

[ioanarusiczki]

@eviljeff

Yes, it's been a bit difficult to understand what is going on but after making a comparison on the API versus dev hub I found some issues:
#19333
#19334
#19335