===Background
In usability testing it was found that some templates have a large number of parameters but few in use, which can make it hard to navigate and get an overview. This effect is multiplied significantly when dealing with multi-part template content. This ticket will help for both single and multi- situations, but a follow up ticket will expand on the multi-part situation.
===Requirements
[] Add OOUI quiet progressive button with icon `eye` or `eyeClosed` depending on the state below the search bar and above the parameter list
[] When unused parameters are shown, the button should use the `eyeClosed` icon and the label should be `Hide unused`. When clicked, all unused parameters are hidden and the button switches states.
[] When unused parameters are hidden, the button should use the `eye` icon and the label should be `Show all fields`. When the clicked, all unused parameters are shown and the button switches states.
[] When user types into the parameter search bar, then the hide/show filtering is temporarily disabled and the button is hidden. Results always show both checked and unchecked results. When the search term is cleared, the filter is re-enabled and is sticky to whatever it was set to before the user starting using the search.
**Nice to have**
[] When single templates are opened or inserted, the default state is unused parameters are shown
[] When multi-part templates are opened, the default state is unused parameters are hidden //Note: In story time it was discussed this might give an opportunity to help improve performance. This was not explicitly made part of this ticket but could be a follow-up ticket. If there is relevant information learned in the course of this work, then it should be noted here.//
===Mocks
{F34908377}
{F34908378}
{F34908381}