gts4lv-common: rro_overlays: Drop explicit 'sdk_version' declaration

* We don't need to manually set this anymore.

Change-Id: I1239ba541636e53f8ea4373d3815024f2cd60824

rro_overlays/WifiOverlay/Android.bp

@@ -1,6 +1,5 @@
 runtime_resource_overlay {
     name: "WifiOverlay",
     theme: "WifiOverlay",
-    sdk_version: "current",
     product_specific: true
 }