delta_calibrate: Do not automatically run G28 on DELTA_CALIBRATE

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

docs/Delta_Calibrate.md

@@ -46,6 +46,7 @@ eliminates error introduced by the probe.
 To perform the basic probe, make sure the config has a
 [delta_calibrate] section defined and run:
 ```
+G28
 DELTA_CALIBRATE METHOD=manual
 ```
 After probing the seven points new delta parameters will be

klippy/extras/delta_calibrate.py

@@ -269,7 +269,6 @@ class DeltaCalibrate:
         self.save_state(probe_positions, distances, new_params)
     cmd_DELTA_CALIBRATE_help = "Delta calibration script"
     def cmd_DELTA_CALIBRATE(self, params):
-        self.gcode.run_script_from_command("G28")
         self.probe_helper.start_probe(params)
     def do_extended_calibration(self):
         # Extract distance positions