Update circuits widget sizing behavior

This change fixes a few quirks of the `Circuit` widget, specifically:

 - if the width of the widget is greater than the width of the cell output area, scroll bars are added, and
 - setting a custom zoom level by changing the value in the zoom control disables the resize handling so that VS Code doesn't incorrectly trigger a recalculation of the default zoom and undo the manual change.

Confirmed with manual testing that window resizing in VS Code circuit display is still hadled properly.

npm/qsharp/ux/circuit.tsx

@@ -77,7 +77,7 @@ function ZoomableCircuit(props: { circuit: qviz.Circuit }) {
     <div>
       <div>
         {rendering ? null : (
-          <ZoomControl zoom={zoomLevel} onChange={setZoomLevel} />
+          <ZoomControl zoom={zoomLevel} onChange={setCustomZoomLevel} />
         )}
       </div>
       <div>
@@ -103,6 +103,16 @@ function ZoomableCircuit(props: { circuit: qviz.Circuit }) {
     }
   }
 
+  /**
+   * Set a custom zoom level. This will disable the automatic resizing by removing the resize event listener,
+   * which will prevent the zoom level from being recalculated immediately based on the new window width.
+   * Resize events will still get handled the next time the window is redrawn or other properies are updated.
+   */
+  function setCustomZoomLevel(zoom: number) {
+    window.removeEventListener("resize", onResize);
+    setZoomLevel(zoom);
+  }
+
   /**
    * Update the width of the SVG element based on the current zoom level.
    */

widgets/src/qsharp_widgets/__init__.py

@@ -179,3 +179,4 @@ class Circuit(anywidget.AnyWidget):
     def __init__(self, circuit):
         super().__init__()
         self.circuit_json = circuit.json()
+        self.layout.overflow = "visible scroll"