Adding new About.Contact (missing) translation and merging About localization keys, for en-US and pt-BR locales

[cassiano]

Fixes #3692

Changes:

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123
• meets the standards outlined in the accessibility guidelines

[cassiano]

Please notice the original Contact localization key had no translation at all, in any of the locales, including the default one (en-US). I renamed it to About.Contact, due to the fact that it is primarily used in the About page.

[cassiano]

I also found out that the About key itself had 2 (identical) translation entries/keys: Nav.Help.About and About.Title. So I decided to merge both into the 2nd one.

[raclim]

Thank you so much for catching this and following up with the changes so promptly!