SDIC Widget should escape to text edit if the plugin is disabled

[SrNetoChan]

If you open a layer that uses the SDIC Widget, but you don't have the plugin enabled or installed, opening the feature form will show the following error:

Although this is somehow expected, would be better if the layer would use text editor as an escape root.

[SrNetoChan]

Thinking about this, probably this can only be achieved in QGIS Core.

[volaya]

The widget type is written in the project file, and it's QGIS which tries to create the widget. The plugin just return the widget when queried.

But if the plugin is not enabled, there is nothing we can do.