Several view specific menu items are not enabled/disabled correctly when views are locked

[gkronber]

The menu items listen to the active-view-changed event of the optimizer to change the enabled/disabled state depending on the active view. However, currently these menu items do not care about the "locked" or "readonly" state of the view. For instance while an algorithm is running it should not be possible to export a data analysis solution to excel.

The following menu items are affected:

• "Export to excel"
• "Create solution ensembles"
• "Remove duplicate datasets"