Update content to use sentence casing

[georgewrmarshall]

Description

Currently, we are inconsistent with our content casing conventions across the app.

This is a problem because although subtle it causes inconsistencies across our app and impacts our brand, accessibility and the message we convey to our users.

In order to solve this problem, all content should use sentence casing unless it falls into the valid exceptions

Technical Details

• Update all content in locales/languages/en.json that should use sentence case to use sentence case

Acceptance Criteria

• All content that should use sentence case should be sentence cased

References

• Extension PR for the same issue

[cortisiko]

@Cal-L @jpcloureiro can one of you take this issue please? Thanks!