The workspace switcher blocks state updates while the indicator is
animating. Since commit 9c1940ef9db5 the indicator is considered to
be animating when the workspace adjustment's value doesn't equal the
active workspace.
There is one case though where this breaks badly: When a workspace
is inserted before the active one, the adjustment's upper and value
properties are changed without transitions. But if that change happens
while there's an ongoing transition to the previously active workspace,
the value gets out of sync with the active workspace and we end up
blocking state updates indefinitely.
Fix this by removing any transitions before setting the adjustment
value.
https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2625
2e80995f19