widgets are not rendered in all clients in RTC

[trungleduc]

Description

Let's say I have 2 clients A and B collaborating on the same notebook, the widget is executed in client A, so it is rendered correctly on A but on B it only shows the repr string of the widget.
The root cause is that the _trusted property of OutputAreaModel of the output cell in client A is set to true after the execution but in B this property is not synced through the shared model so Lab refuses to render the widget.

Reproduce

1. Start a collaborative session and create a widget on one client, other clients will display the repr string of created widget.
2. Go to Command Palette and trust the notebook on all clients, the widget will be displayed correctly.

Expected behavior

Widgets are displayed on all clients at execution.

Context

• JupyterLab version: 3.2.0
• ipywidget: 7.6.5

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[hbcarlos]

Hi @trungleduc! Thanks for opening the issue.
The problem is that the trusted property in the CellModel is not shared between clients. By adding this property to the shared models, we will propagate the change to client B and update the property on the OutputAreaModel.
Do you want to open a PR? I can also look at it.

[trungleduc]

Yes i will try to fix it.