Remove UnavailableSymbol from warnings to disable

Bug: 306806877
Test: m checkapi
Change-Id: If8ad3cf37d84ec30c886a0e6d094ea451c4c3d75
diff --git a/java/sdk_library.go b/java/sdk_library.go
index 4ad3907..2987370 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -1755,7 +1755,6 @@
 		"MissingPermission",
 		"SdkConstant",
 		"Todo",
-		"UnavailableSymbol",
 	}
 	droidstubsArgs = append(droidstubsArgs, android.JoinWithPrefix(disabledWarnings, "--hide "))