internal/postgres: don't remove imports in InsertSampleDirectoryTree

The LegacyPackage.Imports field isn't used anywhere.

For golang/go#39629

Change-Id: I9b88c3235faf48a78f66c80c61ac57ac885fb607
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/262764
Trust: Julie Qiu <julie@golang.org>
Run-TryBot: Julie Qiu <julie@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
diff --git a/internal/postgres/test_helper.go b/internal/postgres/test_helper.go
index f49c825..779cf94 100644
--- a/internal/postgres/test_helper.go
+++ b/internal/postgres/test_helper.go
@@ -212,9 +212,6 @@
 		},
 	} {
 		m := sample.LegacyModule(data.modulePath, data.version, data.suffixes...)
-		for _, p := range m.LegacyPackages {
-			p.Imports = nil
-		}
 		if err := testDB.InsertModule(ctx, m); err != nil {
 			t.Fatal(err)
 		}