HTTPClient - Fix case sensitivity for header keys (#2185)

From https://github.com/espressif/arduino-esp32/pull/8713

libraries/HTTPClient/src/HTTPClient.cpp

@@ -955,7 +955,7 @@ void HTTPClient::collectHeaders(const char* headerKeys[], const size_t headerKey
 
 String HTTPClient::header(const char* name) {
     for (size_t i = 0; i < _headerKeysCount; ++i) {
-        if (_currentHeaders[i].key == name) {
+        if (_currentHeaders[i].key.equalsIgnoreCase(name)) {
             return _currentHeaders[i].value;
         }
     }
@@ -982,7 +982,7 @@ int HTTPClient::headers() {
 
 bool HTTPClient::hasHeader(const char* name) {
     for (size_t i = 0; i < _headerKeysCount; ++i) {
-        if ((_currentHeaders[i].key == name) && (_currentHeaders[i].value.length() > 0)) {
+        if ((_currentHeaders[i].key.equalsIgnoreCase(name)) && (_currentHeaders[i].value.length() > 0)) {
             return true;
         }
     }