config manager: require config group and key when setting configuration

runelite-client/src/main/java/net/runelite/client/config/ConfigManager.java

@@ -507,6 +507,11 @@ public class ConfigManager
 
 	public void setConfiguration(String groupName, String profile, String key, String value)
 	{
+		if (Strings.isNullOrEmpty(groupName) || Strings.isNullOrEmpty(key))
+		{
+			throw new IllegalArgumentException();
+		}
+
 		assert !key.startsWith(RSPROFILE_GROUP + ".");
 		String wholeKey = getWholeKey(groupName, profile, key);
 		String oldValue = (String) properties.setProperty(wholeKey, value);