a71-common: WifiOverlay: Drop explicit 'sdk_version' declaration

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

Change-Id: Id79540d7b7709d6dd1711bb4433f49783086018b

rro_overlays/ConnectivityOverlay/Android.bp

@@ -11,6 +11,5 @@ package {
 
 runtime_resource_overlay {
     name: "ConnectivityOverlay",
-    sdk_version: "current",
     vendor: true
 }

rro_overlays/SoftapOverlay/Android.bp

@@ -7,6 +7,5 @@
 runtime_resource_overlay {
     name: "SoftapOverlay",
     theme: "SoftapOverlay",
-    sdk_version: "current",
     vendor: true
 }

rro_overlays/TetheringOverlay/Android.bp

@@ -8,5 +8,4 @@ runtime_resource_overlay {
     name: "TetheringConfigOverlay",
     resource_dirs: ["res"],
     vendor: true,
-    sdk_version: "current",
 }

rro_overlays/WifiOverlay/Android.bp

@@ -7,6 +7,5 @@
 runtime_resource_overlay {
     name: "WifiOverlay",
     theme: "WifiOverlay",
-    sdk_version: "current",
     vendor: true
 }