Replace SortedStringKeys with SortedKeys

Now that we have generics.

Bug: 193460475
Test: presubmits
Change-Id: I1594fd8feb505175d5c09c03ef397e5ffd5b09cb
diff --git a/android/defaults.go b/android/defaults.go
index 925eafc..a821b28 100644
--- a/android/defaults.go
+++ b/android/defaults.go
@@ -302,7 +302,7 @@
 			delete(propertiesSet, "visibility")
 
 			// Replace the "*" with the names of all the properties that have been set.
-			protectedProperties = SortedStringKeys(propertiesSet)
+			protectedProperties = SortedKeys(propertiesSet)
 			module.setProtectedProperties(protectedProperties)
 		} else {
 			for _, property := range protectedProperties {