Revert^2 "Make embedded_launcher true by default"

This reverts commit 578066be90d3e1960c02b5c80c29e92bca70a70b.

Reason for revert: Relanding

Change-Id: I63f01362cc11c02c4800ae1c21652c7cf4b8a799
diff --git a/python/binary.go b/python/binary.go
index d6750c6..c84eeee 100644
--- a/python/binary.go
+++ b/python/binary.go
@@ -203,7 +203,7 @@
 }
 
 func (p *PythonBinaryModule) isEmbeddedLauncherEnabled() bool {
-	return Bool(p.properties.Embedded_launcher)
+	return BoolDefault(p.properties.Embedded_launcher, true)
 }
 
 func (b *PythonBinaryModule) autorun() bool {