Cleanup python version properties

Now that python 2 is fully removed, there's no need for
version-specific properties. Remove them.

Also remove usages of embedded_launcher: true, as that
is the new default value.

Bug: 399954452
Test: Presubmits
Change-Id: Ibb803cac143a08f3c65e987dee7a88ac338e4496
diff --git a/build/apex/Android.bp b/build/apex/Android.bp
index 20f44fe..79675cb 100644
--- a/build/apex/Android.bp
+++ b/build/apex/Android.bp
@@ -251,11 +251,6 @@
     srcs: [
         "sign_virt_apex.py",
     ],
-    version: {
-        py3: {
-            embedded_launcher: true,
-        },
-    },
     required: [
         // sign_virt_apex should be runnable from outside the source tree,
         // therefore, any required tool should be listed in build/make/core/Makefile as well.
@@ -324,11 +319,6 @@
     srcs: [
         "replace_bytes.py",
     ],
-    version: {
-        py3: {
-            embedded_launcher: true,
-        },
-    },
 }
 
 // Encapsulate the contributions made by the com.android.virt to the bootclasspath.