What?

Refactors the findOrCreate term method to not call the API if the user category already exists, and fixes a bug that allowed different cased labels that could then not be selected.

Why?

• There is no point in calling the API if we already have the category and the id
• The ability to save different cased versions of a category, but then not select them while an edge case has the potential for confusion

How?

• Changed the way the categoryMap is generated to allow identifying of existing user categories and just return the id if exists rather than relying on failed API call to return the existing id as happens in the flat term selector component
• Lower case the categoryMap key to prevent duplicate terms with different casing being added

Testing Instructions

• Remove all the user pattern categories from a site
• Add a pattern and assign a brand new category that doesn't already exist as a core category, eg. Horses
• Check that the /v2/wp_pattern_category endpoint was called and the category was added successfully
• Add a new pattern and assign the same Horses category and check that /v2/wp_pattern_category was not called and the category was successfully assigned to the pattern
• Add a new pattern and select the core pattern category Headers
• Check that a user category of Headers was added with slug of header
• In a site with no user categories add a new pattern and assign the category banners with lower case b and check that the category is added as Banners to match the existing core category