Add ability to pass translation strings into character count component via JS

[vanitabarrett]

What

Add ability for users to pass a translation object in via JavaScript (at the point of initialisation). This is an alternative method to passing translation strings via the Nunjucks macros (data-attributes).

Note: this may already have been covered by all the previous internationalisation tickets. Even if we don’t need to write additional code to get this working, we should ensure it’s tested.

Why

Some users may prefer to pass translation strings via JavaScript, or it may be better suited to their service.

Who needs to work on this

Developers

Who needs to review this

Developers

Done when

• It’s possible to provide translations to the character count component via JavaScript
• The character count component has tests which cover the ability to translate via JavaScript
• The character count component still works if no/only some translations are passed (falls back to defaults)
• Data attribute translations take priority over JS translations, if both provided