Issue description

The federal agency dropdown uses the Select USWDS component, but there are a lot of items in the list leading to a less than ideal UX. Currently, users have to navigate a massive list just by scrolling, with a combo box, they can narrow the list down by typing in a keyword first. This same problem also occurs on the state / territory dropdowns on the request form and management pages. USWDS's recommends using the select component when the user has to select from a small number of items and recommends the combo box component when the number of items is more than 15.

From the USWDS guidance:

Use a combo box when there are more than 15 choices in a drop-down list. With so many options, users may find it difficult to navigate with scrolling only.

Use the select component only when a user needs to choose from about seven to 15 possible options and you have limited space to display the options.

Acceptance criteria

• change federal agency dropdown from select to combo box on the request form
• change federal agency dropdown from select to combo box on the organization name and mailing address page on the request form (note that this dropdown is disabled right now, but we should make sure the component is matching the request form).
• change State, territory, or military post dropdown on Organization name and mailing address in the request form and domain management pages

Additional context

See slack thread for more details

Links to other issues

No response