[django-flat-json-widget] QA: add frontend tests

[nemesifier]

Add frontend testing:

• add row
• delete row
• toggle textarea
• edit json from textarea
• go back to widget mode and ensure the JSON edited from the textarea displays correctly

[InfiniteVerma]

Hi. I would like to work on this.

[atb00ker]

You don't need to wait for assignment.
You can start working on it and create a PR.
The simple rule is that if there is a recent PR opened for an issue, ask before working on it.
If there is no activity, feel free to start. 😄

[harsh7in]

Hi, I think anyone is not working on this issue, so I would like to work on this issue.

[Rani-Boora]

Hey nemesifier,
I am interested in this issue,could you please assign this to me.

[arshika-afza3]

hello there
My Name is Arshika Afza
I am interested into this issue would you like to assign me with this :) .

[nemesifier]

You guys don't read, do you?

You don't need to wait for assignment.

[Eeshu-Yadav]

working on that