Non user-friendly error message when trying to save a workflow without any action metadata provided (name, entrypoint, etc.)

[Kami]

If you click "Save Workflow" button before providing any workflow metadata info in the right page (name, entry point, etc.), we just should "Error saving workflow" error message.

We should make that error more useful and friendly. Should probably say something along the lines of "Error saving workflow - fields name and entry point are mandatory". And perhaps also indicate that with * next to the fight in the right pane.

[bmomberger-bitovi]

The ToolbarButton component only accepts a single fixed string for when the operation fails when the button is clicked. Currently that string is "Error saving workflow" so that's the only error that's generated. Instead of using this feature, remove the errorMessage property and report errors directly with PUSH_ERROR in the save() function.