Remove the approval dashbaord view when the module is uninstalled

[andybroomfield]

Experincing an error when uninstalling and reinstalling localgov_workflows. The view localgov_approvals_dashboard remains,

Configuration objects (views.view.localgov_approvals_dashboard) provided by localgov_workflows already exist in active configuration

I don't think the view has much utility outside of localgov_workflows, so it should be uninstalled when the module is.

[stephen-cox]

Should be fixed with #19