feat: enable pt_PT and zh_Hans as supported languages

[cfm]

• Depends on Translations update from Weblate #1527

Description

As of #1527, 2 languages are 100% translated and approved (listed in Weblate sort order)

1. zh_Hans: Chinese (Simplified)
2. pt_PT: Portuguese (Portugal)

Another 5 are 100% translated but only partially approved (listed in Weblate sort order):

3. de: German
4. ca: Catalan
5. is: Icelandic
6. sv: Swedish
7. tr: Turkish

To err on the side of conservatism for now, here we enable only pt_PT and zh_Hans as 100% translated and approved.

Test Plan

• Both pt_PT and zh_Hans are packaged:

  (.venv) user@sd-dev:~/securedrop-client$ python setup.py sdist 2> /dev/null | grep -E "(pt_PT|zh_Hans)"
  creating securedrop-client-0.7.0/securedrop_client/locale/pt_PT
  creating securedrop-client-0.7.0/securedrop_client/locale/pt_PT/LC_MESSAGES
  creating securedrop-client-0.7.0/securedrop_client/locale/zh_Hans
  creating securedrop-client-0.7.0/securedrop_client/locale/zh_Hans/LC_MESSAGES
  copying securedrop_client/locale/pt_PT/LC_MESSAGES/messages.mo -> securedrop-client-0.7.0/securedrop_client/locale/pt_PT/LC_MESSAGES
  copying securedrop_client/locale/pt_PT/LC_MESSAGES/messages.po -> securedrop-client-0.7.0/securedrop_client/locale/pt_PT/LC_MESSAGES
  copying securedrop_client/locale/zh_Hans/LC_MESSAGES/messages.mo -> securedrop-client-0.7.0/securedrop_client/locale/zh_Hans/LC_MESSAGES
  copying securedrop_client/locale/zh_Hans/LC_MESSAGES/messages.po -> securedrop-client-0.7.0/securedrop_client/locale/zh_Hans/LC_MESSAGES

• Install this package into your venv:

  (.venv) user@sd-dev:~/securedrop-client$ pip install dist/securedrop-client-0.7.0.tar.gz

• The Client loads in Portuguese (Portugal):

  (.venv) user@sd-dev:~/securedrop-client$ LANG=pt_PT .venv/bin/sd-client

• The Client loads in Chinese (Simplified):

  (.venv) user@sd-dev:~/securedrop-client$ LANG=zh_Hans .venv/bin/sd-client

Checklist

If these changes modify code paths involving cryptography, the opening of files in VMs or network (via the RPC service) traffic, Qubes testing in the staging environment is required. For fine tuning of the graphical user interface, testing in any environment in Qubes is required. Please check as applicable:

• I have tested these changes in the appropriate Qubes environment
• I do not have an appropriate Qubes OS workstation set up (the reviewer will need to test these changes)
• These changes should not need testing in Qubes

If these changes add or remove files other than client code, the AppArmor profile may need to be updated. Please check as applicable:

• I have updated the AppArmor profile
• No update to the AppArmor profile is required for these changes
• I don't know and would appreciate guidance

If these changes modify the database schema, you should include a database migration. Please check as applicable:

• I have written a migration and upgraded a test database based on main and confirmed that the migration is self-contained and applies cleanly
• I have written a migration but have not upgraded a test database based on main and would like the reviewer to do so
• I need help writing a database migration
• No database schema changes are needed

[cfm]

This pull request did not make it into v0.8.0, so we'll need to reassess translation coverage for supported languages for the next release.

[eloquence]

As discussed, taking this for a spin; if all looks good, we should be able to turn those languages on for 0.9.0.

[eloquence]

(Rebased to main.)

[eloquence]

• Both pt_PT and zh_Hans are packaged:

I built a full package from the branch and installed in sd-small-bullseye-template rather than the venv method, and verified that I was able to switch languages to Portuguese (Portugal) and Simplified Chinese. There are a couple of issues with translation support that I'll file separately, but I don't think that needs to hold up merging initial support for languages that have complete coverage.

• The Client loads in Portuguese (Portugal):
• The Client loads in Chinese (Simplified):