Make the Tudor Crown logo the default and deprecate the useTudorCrown parameter

[querkmachine]

What

Deprecate the useTudorCrown parameter on the Header component.

At the same time, invert the component's logic so that using the Tudor Crown logo becomes the default that users must explicitly opt-out of, rather than opt-in to having.

Why

The new crown and logo will launch with Frontend v5.1.

This is estimated to be released w/c 15th January 5th February. However, services will be asked not to update to the new logo until 19th February, after public-facing comms about the logo change have been released.

To help manage this date discrepancy and the 'breakingness' of what would normally be considered a breaking change, the Header Nunjucks component provides the Tudor Crown logo as an opt-in feature, in the same manner as the v4.8 and v3.15 releases.

However, as new projects should use the Tudor Crown, it doesn't make sense to keep this feature opt-in for very long, and we probably want to switch it be the default after a short 'transition period'.

Who needs to work on this

• Developers

Who needs to review this

• Developers

Done when

• Alter the logic of useTudorCrown so that it is true by default
• Update tests to account for this change
• The useTudorCrown parameter is marked as deprecated