internal/frontend: do not set SearchMode by default

By default, set m="" instead of m="package".

For golang/go#44142

Change-Id: I2a9c53a4a5bf7f9cd7056996621ef82b0e0f25d2
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/346534
Trust: Julie Qiu <julie@golang.org>
Run-TryBot: Julie Qiu <julie@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
diff --git a/internal/frontend/server.go b/internal/frontend/server.go
index 081e4f2..69d41e9 100644
--- a/internal/frontend/server.go
+++ b/internal/frontend/server.go
@@ -309,7 +309,6 @@
 		DevMode:            s.devMode,
 		AppVersionLabel:    s.appVersionLabel,
 		GoogleTagManagerID: s.googleTagManagerID,
-		SearchMode:         searchModePackage,
 		SearchModePackage:  searchModePackage,
 		SearchModeSymbol:   searchModeSymbol,
 	}