Add a `blocklyToolboxFlyout` CSS class to the flyout if it is used by the toolbox

[Beka Westberg]

In the init method on the toolbox before inserting the result of this.flyout.createDom into the dom call dom.addClass with the created DOM element and blocklyToolboxFlyout.

This change should be made against the rc/v12.0.0 branch.

To work on this issue, comment below asking to be assigned.

[Suryansh Shakya]

Hi @BeksOmega , I would like to work on this issue.

[Shreshtha Sharma]

Hey @BeksOmega, I would like to work on this issue. Kindly assign it to me.

[Beka Westberg]

Go for it @nullHawk =)

[Suryansh Shakya]

Hi @BeksOmega, I have raised the PR, please have a look at it

[Beka Westberg]

Closed by #8386