[i18n] Translation IDs are not being resolved for pt-BR or zh-CN, or they are but with warnings

[chalin]

For details, see:

• [pt][i18n] Add Portuguese translations for alert types #8469

The PR adds pt.toml which results in warnings because we're hitting:

• Hugo cannot identity correct translation string when multiple variants of a language code is used gohugoio/hugo#7982

The PR adds the warnings to our warning skip list but I think that we can do better. Hugo should look for and use the languageCode translations if available. I (@chalin) will look into this.

[chalin]

To be clear, the following PR triggers the reading of pt-br.toml, but the alert IDs in pt.toml are being ignored.