Webserver Ignore extra headers in multipart forms

From espressif/arduino-esp32#9253

Author: earlephilhower

libraries/WebServer/src/Parsing.cpp

@@ -448,11 +448,12 @@ bool HTTPServer::_parseForm(WiFiClient * client, String boundary, uint32_t len)
                     argType = FPSTR(mimeTable[txt].mimeType);
                     line = client->readStringUntil('\r');
                     client->readStringUntil('\n');
-                    if (line.length() > 12 && line.substring(0, 12).equalsIgnoreCase(FPSTR(Content_Type))) {
-                        argType = line.substring(line.indexOf(':') + 2);
-                        //skip next line
-                        client->readStringUntil('\r');
-                        client->readStringUntil('\n');
+                    while (line.length() > 0) {
+                        if (line.length() > 12 && line.substring(0, 12).equalsIgnoreCase(FPSTR(Content_Type))) {
+                            argType = line.substring(line.indexOf(':') + 2);
+                        }
+                        //skip over any other headers
+                        line = client->readStringUntil('\r');
                     }
                     log_v("PostArg Type: %s", argType.c_str());
                     if (!argIsFile) {