Revert 'OFW/gsurkov/vcp_break_support' changes

avr_isp/helpers/avr_isp_worker.c

@@ -55,7 +55,6 @@ static const CdcCallbacks cdc_cb = {
     vcp_state_callback,
     vcp_on_cdc_control_line,
     vcp_on_line_config,
-    NULL,
 };
 
 /* VCP callbacks */

gpio_reader_b/usb_uart_bridge.c

@@ -70,7 +70,6 @@ static const CdcCallbacks cdc_cb = {
     vcp_state_callback,
     vcp_on_cdc_control_line,
     vcp_on_line_config,
-    NULL,
 };
 
 /* USB UART worker */

swd_probe/usb_uart.c

@@ -49,7 +49,6 @@ static const CdcCallbacks cdc_cb = {
     .state_callback = &vcp_state_callback,
     .ctrl_line_callback = &vcp_on_cdc_control_line,
     .config_callback = &vcp_on_line_config,
-    .break_callback = NULL,
 };
 
 static void usb_uart_vcp_init(UsbUart* usb_uart, uint8_t vcp_ch) {