autotest: give Rover longer to arrive home

vagaries of interaction with Python script means we need to give this more time when running balancebot
Backport of PR https://github.com/ArduPilot/ardupilot/pull/23442

Tools/autotest/rover.py

@@ -1295,17 +1295,21 @@ Brakes have negligible effect (with=%0.2fm without=%0.2fm delta=%0.2fm)
         self.wait_ready_to_arm()
         self.arm_vehicle()
 
+        # calculate early to avoid round-trips while vehicle is moving:
+        accuracy = self.get_parameter("WP_RADIUS")
+
         self.reach_heading_manual(10)
         self.reach_distance_manual(50)
 
         self.change_mode("RTL")
+
         # location copied in from rover-test-rally.txt:
         loc = mavutil.location(40.071553,
                                -105.229401,
                                0,
                                0)
-        accuracy = self.get_parameter("WP_RADIUS")
-        self.wait_location(loc, accuracy=accuracy, minimum_duration=10)
+
+        self.wait_location(loc, accuracy=accuracy, minimum_duration=10, timeout=45)
         self.disarm_vehicle()
 
     def fence_with_bad_frame(self, target_system=1, target_component=1):