Default to All items when Searching within this Collection

Description: When a user searches “within this collection” in the search box from a collection page, the search results should default to “All items” and not “Grouped by collection.” We still want searching across all collections to default to “Grouped by collection”, however.

Related: #151 (closed)

Documentation (More Info): https://docs.google.com/document/d/13CST-ZD9wpbx--ISyhlw_zyxFczbkJTSKUh5L6FFqgY/edit?usp=sharing