Fix linked clamps bug (did not update properly)

src/classy_blocks/modify/grid.py

@@ -57,6 +57,7 @@ def update(self, junction: Junction) -> None:
         if junction.clamp is not None:
             if junction.clamp.is_linked:
                 linked_junction = self.get_junction_from_clamp(junction.clamp)
+                self.points[linked_junction.vertex.index] = linked_junction.vertex.position
                 for cell in linked_junction.cells:
                     cell.invalidate()
 
@@ -82,4 +83,4 @@ def clamps(self) -> List[ClampBase]:
     @property
     def quality(self) -> float:
         """Returns summed qualities of all junctions"""
-        return sum([junction.quality for junction in self.junctions])
+        return sum([cell.quality for cell in self.cells])

src/classy_blocks/modify/junction.py

@@ -5,10 +5,6 @@
 from classy_blocks.modify.clamps.clamp import ClampBase
 
 
-class ClampExistsError(Exception):
-    """Raised when attempting to add a vertex that's already among existing clamps"""
-
-
 class Junction:
     """A class that collects Cells/Blocks that
     share the same Vertex"""
@@ -28,9 +24,6 @@ def add_cell(self, cell: Cell) -> None:
                 return
 
     def add_clamp(self, clamp: ClampBase) -> None:
-        if self.clamp is not None:
-            raise ClampExistsError(f"A clamp has already been defined for vertex {self.vertex}")
-
         self.clamp = clamp
 
     @property