[Docs] StageWebView::drawViewPortAsync() call error without viewPort not documented

[itlancer]

Problem Description

StageWebView::drawViewPortAsync() call error without viewPort not documented.
It could be throwed by

stageWebView.drawViewPortAsync(bimapData);

if StageWebView::viewPort not set up.
In this case you will get exception:

ArgumentError: Error #2004: One of the parameters is invalid.
        at flash.media::StageWebView/drawViewPortAsync()

but it's not documented properly as a reason.

Steps to Reproduce

https://airsdk.dev/reference/actionscript/3.0/flash/media/StageWebView.html#drawViewPortAsync()

Actual Result:
null viewPort reason not documented.

Expected Result:
null viewPort reason documented.