remove helper class

Author: mbfreder

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsAlbHttpServletRequest.java

@@ -465,21 +465,21 @@ protected String[] getFormBodyParameterCaseInsensitive(String key) {
         }
     }
 
-    protected String getFirst(Map<String, List<String>> map, String key) {
+    public static String getFirst(Map<String, List<String>> map, String key) {
         List<String> values = map.get(key);
         if (values == null || values.size() == 0) {
             return null;
         }
         return values.get(0);
     }
 
-    protected void putSingle(Map<String, List<String>> map, String key, String value) {
+    public static void putSingle(Map<String, List<String>> map, String key, String value) {
         List<String> values = findKey(map, key);
         values.clear();
         values.add(value);
     }
 
-    protected List<String> findKey(Map<String, List<String>> map, String key) {
+    public static List<String> findKey(Map<String, List<String>> map, String key) {
         List<String> values = map.get(key);
         if (values == null) {
             values = new ArrayList<>();