drv/technic_hub/bluetooth: respond to find by type value request

Windows has recently started sending a find by type value request.
We need to send some sort of response, otherwise Bluetooth just hangs.
For now, we just send an error, but could implement this properly in
the future.

Issue: pybricks/support#136

Author: dlech

lib/pbio/drv/technic_hub/bluetooth.c

@@ -359,6 +359,28 @@ static void handle_event(uint8_t *packet) {
                     ATT_ExchangeMTURsp(connection_handle, &rsp);
                 }
                 break;
+
+                case ATT_EVENT_FIND_BY_TYPE_VALUE_REQ: {
+                    uint16_t start_handle = (data[7] << 8) | data[6];
+                    uint16_t end_handle = (data[9] << 8) | data[8];
+                    uint16_t type = (data[11] << 8) | data[10];
+                    uint8_t *value = &data[12];
+
+                    UNUSED(start_handle);
+                    UNUSED(end_handle);
+                    UNUSED(type);
+                    UNUSED(value);
+
+                    DBG("s %04X t %04X", start_handle, type);
+                    attErrorRsp_t rsp;
+
+                    rsp.reqOpcode = ATT_FIND_BY_TYPE_VALUE_REQ;
+                    rsp.handle = start_handle;
+                    rsp.errCode = ATT_ERR_UNSUPPORTED_REQ;
+                    ATT_ErrorRsp(connection_handle, &rsp);
+                }
+                break;
+
                 case ATT_EVENT_READ_BY_TYPE_REQ: {
                     uint16_t start_handle = (data[7] << 8) | data[6];
                     uint16_t end_handle = (data[9] << 8) | data[8];