Add null check for readyState in InterceptAjaxRequestJS

[furkankurt]

Add null check for readyState in InterceptAjaxRequestJS to skip events that are not done.

Connection with issue(s)

Resolve issue #2197

Connected to #404

Testing and Review Notes

To fix that issue, I've referenced this URL.

Screenshots or Videos

To Do

• double check the original issue to confirm it is fully satisfied
• add testing notes and screenshots in PR description to help guide reviewers
• request the "UX" team perform a design review (if/when applicable)

[bjoernpy]

Any idea when this could be released?

[arrrrny]

@furkankurt @bjoernpy @daanporon @kamilpowalowski @cbodin
Open your PR on the forked project here and I will merge. There is a new package now. zikzak_inappwebview