Remove prebuilt_visibility from sdk

This property was introduced for inter module dependencies in the
prebuilt module sdk. https://r.android.com/3252814 changed the visibilty
of all prebuilts in module sdk to //visibility:public. This property is
a noop now, and can be removed.

Test: go test ./sdk
Bug: 365111645
Change-Id: I186a201895fc2b33a65bbedae8a8326e087feb2b

sdk/sdk_test.go

@@ -53,9 +53,6 @@ func TestSnapshotVisibility(t *testing.T) {
 				// generated sdk_snapshot.
 				":__subpackages__",
 			],
-			prebuilt_visibility: [
-				"//prebuilts/mysdk",
-			],
 			java_header_libs: [
 				"myjavalib",
 				"mypublicjavalib",
@@ -162,18 +159,6 @@ java_import {
 `))
 }
 
-func TestPrebuiltVisibilityProperty_IsValidated(t *testing.T) {
-	testSdkError(t, `prebuilt_visibility: cannot mix "//visibility:private" with any other visibility rules`, `
-		sdk {
-			name: "mysdk",
-			prebuilt_visibility: [
-				"//foo",
-				"//visibility:private",
-			],
-		}
-`)
-}
-
 func TestSdkInstall(t *testing.T) {
 	sdk := `
 		sdk {