[Bug 22211] Remove unnecessary 'unlock cursor' in ideMouseMove

[BerndN]

This patch removes a seemingly unnecessary unlock cursor in the IDE's mouseMove event handler (ideMouseMove).

The IDE intercepts mouseMove so that it can update the resize cursor used when the mouse is over the relevant selection handlers. It does this by locking the cursor in this case and then changing the cursor appropriately; unlocking the cursor when there is a selected object and the mouse is not over a selection handle.

Previously it would also unlock the cursor if pointer tool was in effect and there was no selected object which (because the handler is executed in time after any user handlers) would undo any user use of lock cursor.

This fixes bug 22211 and bug 18428 and avoids the problems of a fix for these in https://github.com/livecode/livecode-ide/pull/2092