autotest: remove unnecessary try/except from Sprayer test

backport from https://github.com/ArduPilot/ardupilot/pull/23823

Tools/autotest/arducopter.py

@@ -9467,8 +9467,7 @@ class AutoTestCopter(AutoTest):
     def Sprayer(self):
         """Test sprayer functionality."""
         self.context_push()
-        ex = None
-        try:
+
         rc_ch = 9
         pump_ch = 5
         spinner_ch = 6
@@ -9563,15 +9562,12 @@ class AutoTestCopter(AutoTest):
                      0)  # p7
         self.wait_servo_channel_value(pump_ch, pump_ch_min)
 
-            self.progress("Sprayer OK")
-        except Exception as e:
-            self.print_exception_caught(e)
-            ex = e
         self.context_pop()
+
         self.disarm_vehicle(force=True)
         self.reboot_sitl()
-        if ex:
-            raise ex
+
+        self.progress("Sprayer OK")
 
     def tests1a(self):
         '''return list of all tests'''
@@ -9749,7 +9745,7 @@ class AutoTestCopter(AutoTest):
         self.reboot_sitl()
         self.wait_ready_to_arm()
         self.takeoff(alt_min=20, mode='LOITER')
-        self.land_and_disarm()
+        self.do_RTL()
         self.context_pop()
         self.reboot_sitl()