Fixes to Spanish translation

[jorgesumle]

Description

It fixes really ugly translations and mistakes (it looks like some strings were translated by a machine).

Pull Request - Checklist

• Initial Manual Tests Passed
• Double check modified code and verify it with the feature/task requirements
• Format code
• Look for code duplication
• Clear naming for variables and methods
• Manual tests in accessibility mode (TalkBack on Android) passed

I have a question: should the Spanish translation use "usted" (formal) or "tú" (informal)? It looks like the Spanish translation is inconsistent in this regard: sometimes it uses "usted", other times it uses "tú".

No sé quién ha contribuido principalmente a la traducción al español o quién debería decidir esto, pero creo que se debe elegir o si se usa usted o tú, y no mezclarlos (@ktecho).

[jorgesumle]

Oh, and the text returned from the getOrdinal function in lib/src/screens/seed/seed_verification/seed_verification_step_view.dart is not translatable. In Spanish it should return "1.ª", "2.ª", "3.ª" and so on, as the word "palabra" is feminine. I think that should be an issue not only for Spanish, but also for other languages. I haven't fixed that.

[rottenwheel]

Looks good to me. @OmarHatem28 please merge #2408 before this one, 2407, so that there's no conflicts. Thanks!