chore: remove references to dbtestutil.WillUsePostgres (#20436)

Addresses https://github.com/coder/internal/issues/758.

This PR only cleans up dead code, it makes no changes to test logic.

coderd/database/pubsub/pubsub_test.go

@@ -19,9 +19,6 @@ import (
 
 func TestPGPubsub_Metrics(t *testing.T) {
 	t.Parallel()
-	if !dbtestutil.WillUsePostgres() {
-		t.Skip("test only with postgres")
-	}
 
 	logger := testutil.Logger(t)
 	connectionURL, err := dbtestutil.Open(t)
@@ -122,9 +119,6 @@ func TestPGPubsub_Metrics(t *testing.T) {
 
 func TestPGPubsubDriver(t *testing.T) {
 	t.Parallel()
-	if !dbtestutil.WillUsePostgres() {
-		t.Skip("test only with postgres")
-	}
 
 	ctx := testutil.Context(t, testutil.WaitLong)
 	logger := slogtest.Make(t, &slogtest.Options{