Remove "flattened" apexes

Now soong doesn't build "flattened" apexes.

Bug: 279835185
Test: m nothing (soong tests)
Test: m && launch_cvd (cuttlefish)
Change-Id: Id3c540ece1a15cecacc185da9aa17285edd2f493
diff --git a/apex/prebuilt.go b/apex/prebuilt.go
index 0d83830..3509e6c 100644
--- a/apex/prebuilt.go
+++ b/apex/prebuilt.go
@@ -133,9 +133,7 @@
 }
 
 func (p *prebuiltCommon) checkForceDisable(ctx android.ModuleContext) bool {
-	// If the device is configured to use flattened APEX, force disable the prebuilt because
-	// the prebuilt is a non-flattened one.
-	forceDisable := ctx.Config().FlattenApex()
+	forceDisable := false
 
 	// Force disable the prebuilts when we are doing unbundled build. We do unbundled build
 	// to build the prebuilts themselves.