fixes clear cell outputs command and improves toolbar creation

[jonah-iden]

What it does

This fixes the clear cell output and change presentation from the cell sidebar context menu

How to test

Open or create a notebook including a cell with multiple output representations.
For example the following (requires PIL installed in the kernel)

 from PIL import Image

img_1 = Image.new("RGBA", (1600, 200), color="red")

display(img_1)

Check that changing the ouptut presentation works.
Check that clearing the output works.

Follow-ups

There is currently no support for multiple outputs yet. So if you have two outputs both are affected by the actions.
Also it seems there is still a bug with going back to images after changing to text

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[msujew]

This works partially: When initially rendering the output, changing the presentation doesn't work on the first attempt. Only after clearing the output and then rerunning the cell does it work as expected. Also, changing from image to text and then back to image simply removes (?) the output. Only after running the cell again, I get to see the image output. See the attached video:

2024-04-25.15-08-05.mp4

[jonah-iden]

@msujew the sometimes not being able to change the presentation should be fixed, as described in the follow ups the problem with going back to image seems to be a larger one. I would work on that on a separate PR

[msujew]

Alright, in this case, this looks good to me 👍