Toolbox (simple and category) sizes do not get updated properly

[BeksOmega]

Describe the bug

If the workspace is immovable (meaning no movement nor zoom options) blocks will bump themselves back into the space of the workspace to prevent them going off screen:

But when you change the size of the toolbox, this stops working correctly:

The toolbox-side bound seems to obey the previous size of the toolbox, and the opposite-side bound is further towards the toolbox than it should be.

To Reproduce

Steps to reproduce the behavior:

1. Go to replace the playgroundConfig in the advanced playground with the following:

  const playgroundConfig = {
    toolboxes: {
      'categories': toolboxCategories,
      'simple': toolboxSimple,
      'test blocks': testBlocksToolbox,
      'size test 1': '<xml>' +
              '<block type="lists_getIndex"></block>' +
              '</xml>',
      'size test 2': '<xml>' +
              '<category name="short">' +
              '<category name="loooooooooooooooooong">' +
              '<block type="controls-if"></block>' +
              '</category>' +
              '</category>' +
              '</xml>'
    }
  }

2. Disable all movement, including zooming.
3. Select either of the size-test toolboxes.
4. Change the size.
5. Drag a block around to observe the odd bumping behavior.

Expected behavior

Bumping would continue to work as expected after the size of the flyout changes.

Additional context

Possibly related to #4086? Discovered this while investigating that. Note that mutators are immovable workspaces.