Remove "Application" field from ConduitSearchEngine

Summary: Fixes T9063. Removes the "Application" field from the search because it was largely redundant with the 'Name Contains' field.

Test Plan: Went to /conduit/query/modern/, clicked on Edit Query and noted that there is no "Application" field anymore. The 'Name Contains' field still works however.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin, epriestley, yelirekim

Maniphest Tasks: T9063

Differential Revision: https://secure.phabricator.com/D16602