Fix possible hang at startup/add printer

Remove the ISP leaving part which is *probably* unnecessary 99.99% of the times but may cause a hang when some USB devices are connected.

CURA-10972

plugins/USBPrinting/AutoDetectBaudJob.py

@@ -27,14 +27,7 @@ class AutoDetectBaudJob(Job):
         write_timeout = 3
         read_timeout = 3
         tries = 2
-
-        programmer = Stk500v2()
         serial = None
-        try:
-            programmer.connect(self._serial_port)
-            serial = programmer.leaveISP()
-        except ispBase.IspError:
-            programmer.close()
 
         for retry in range(tries):
             for baud_rate in self._all_baud_rates: