CAM: fix G0 regression in drilling (#22602)

* CAM: fix G0 regression in drilling

At some point the initial rapid to Safe Height got dropped from drilling cycles. 
This leads to excessive air drilling.
It also alters "OLD_Z" which sets the Retraction plane under G98.

The defect is causing much confusion and time wasting in the roadmap discussions

This PR fixes the G0 regression.

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/Mod/CAM/Path/Op/Drilling.py

@@ -205,14 +205,13 @@ class ObjectDrilling(PathCircularHoleBase.ObjectOp):
         machine = PathMachineState.MachineState()
 
         self.commandlist.append(Path.Command("(Begin Drilling)"))
+        self.commandlist.append(Path.Command("G90"))  # Set absolute distance mode before any moves
 
         # rapid to clearance height
         command = Path.Command("G0", {"Z": obj.ClearanceHeight.Value})
         machine.addCommand(command)
         self.commandlist.append(command)
 
-        self.commandlist.append(Path.Command("G90"))  # Absolute distance mode
-
         # Calculate offsets to add to target edge
         endoffset = 0.0
         if obj.ExtraOffset == "Drill Tip":
@@ -265,6 +264,7 @@ class ObjectDrilling(PathCircularHoleBase.ObjectOp):
             edgelist.append(Part.makeLine(v1, v2))
 
         # iterate the edgelist and generate gcode
+        safeHeight = True
         for edge in edgelist:
 
             Path.Log.debug(edge)
@@ -279,6 +279,13 @@ class ObjectDrilling(PathCircularHoleBase.ObjectOp):
             self.commandlist.append(command)
             machine.addCommand(command)
 
+            # rapid to safe height for first edge only //Dimitrios
+            if safeHeight is True:
+                command = Path.Command("G0", {"Z": obj.SafeHeight.Value})
+                self.commandlist.append(command)
+                machine.addCommand(command)
+                safeHeight = False
+
             # Technical Debt:  We are assuming the edges are aligned.
             # This assumption should be corrected and the necessary rotations
             # performed to align the edge with the Z axis for drilling