chore(aap): use forwarded as IP pattern (#14400)

APPSEC-58261

Following guidelines on internal document "Client IP addresses
resolution"

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Author: christophe-papazian

ddtrace/contrib/internal/trace_utils.py

@@ -70,6 +70,7 @@
     "x-real-ip",
     "true-client-ip",
     "x-client-ip",
+    "forwarded",
     "forwarded-for",
     "x-cluster-client-ip",
     "fastly-client-ip",

tests/tracer/test_trace_utils.py

@@ -632,7 +632,7 @@ def test_set_http_meta_case_sensitive_headers_notfound(mock_store_headers, span,
     ("x-real-ip", "2.2.2.2"),
     ("true-client-ip", "3.3.3.3"),
     ("x-client-ip", "4.4.4.4"),
-    ("x-forwarded", "5.5.5.5"),
+    ("forwarded", "5.5.5.5"),
     ("forwarded-for", "6.6.6.6"),
     ("x-cluster-client-ip", "7.7.7.7"),
     ("fastly-client-ip", "8.8.8.8"),
@@ -644,8 +644,6 @@ def test_set_http_meta_case_sensitive_headers_notfound(mock_store_headers, span,
 ALL_TESTS = [
     ["", dict(ALL_IP_HEADERS[-1 : -i - 2 : -1]), ALL_IP_HEADERS[-1 - i][1]] for i in range(len(ALL_IP_HEADERS))
 ]
-# x-forwarded is now ignored so we fall back to forwarded-for
-ALL_TESTS[5][2] = "6.6.6.6"
 
 
 @pytest.mark.parametrize(