disable interactive search (splitSearchModes) by default
Created by: sqs
Switches the default back to interactive search mode being disabled. The plain text search input (using Monaco) has gotten a lot smarter since we introduced interactive search mode, and interactive search mode has seen fairly low usage as a % of all searches.
See https://sourcegraph.slack.com/archives/CHEKCRWKV/p1600450926015300?thread_ts=1600443200.010300 for discussion about potentially completely removing interactive search mode in the future. For now, it's still there, but it's disabled by default.