Variable Library: Shortcuts with variable value that doesn't resolve a path should error out.

When using a variable library to actively set shortcut path information (workspace, item, path) if a selected variable value(s) result in a non-existent location, the intentional assignment of the variable value should be forced into the shortcut, which shall cause a shortcut error that would be visible in the left hand lakehouse explorer/navigation (red X or similar error symbol).  

The current default keeps the old or default value, which could erroneously have some shortcuts pointing to the new value while others in the same lakehouse point to an old value.  For example, this could expose DEV tables in a TEST lakehouse when the intended selection of the TEST variable value set is to only show valid shortcuts to underlying TEST location. Other than the error at the time of updating variables on the lakehouse, there is no perminent indication for users in the future that some of the shortcuts are not pointing at the desired location.

Similar to frithjof_v  idea disabling the default value when a variable library is deployed across workspaces and a selection is not made, but differs by forcing an error when a selection is actively made that doesn't resolve to a valid path.  The other speaks to avoiding the default if no selection is made.