BLE: Fix security requirements in GattCharacteristic.

Author: pan-

features/FEATURE_BLE/ble/GattCharacteristic.h

@@ -1412,7 +1412,7 @@ class GattCharacteristic {
         writeAuthorizationCallback(),
         _update_security(SecurityRequirement_t::NONE) {
         _valueAttribute.allowWrite(isWritable(_properties));
-        _valueAttribute.allowWrite(isReadable(_properties));
+        _valueAttribute.allowRead(isReadable(_properties));
 
         if (_properties & BLE_GATT_CHAR_PROPERTIES_AUTHENTICATED_SIGNED_WRITES) {
             _valueAttribute.setWriteSecurityRequirement(