8487 - Adjusted width calculation in searchfield

[yohannahbautista]

Explain the details for making this change. What existing problem does the pull request solve?

When screen is below slim breakpoint (400), the width calculated becomes too big once a category button is included. Put a check if the screen is below 400, add more in subtractWidth (variable used to shorten the searchfield if it includes components like category button).

Related github/jira issue (required):

Closes #8487

Steps necessary to review your pull request (required):

• Pull this branch, build and run the app
• Go to: http://localhost:4000/components/searchfield/example-categories-short.html
• Minimize screen to below 400
• Searchfield should fit

Included in this Pull Request:

• A note to the change log.