pdfs with flattened forms can't be printed in Adobe Reader or Acrobat

[xoapit]

What?

Gets correct widget ref from the document to remove the corresponding annotation ref from the page

Why?

Trying to fix this issue: Hopding#1267
Original discussion: Hopding#1268

How?

Gets the ref using doc.context.getObjectRef instead of findWidgetAppearanceRef (which seems to get the wrong ref?)

Testing?

Ran the unit tests

New Dependencies?

N/A

Screenshots

N/A

Suggested Reading?

N/A

Anything Else?

N/A

Checklist

• I read CONTRIBUTING.md.
• I read MAINTAINERSHIP.md#pull-requests.
• I added/updated unit tests for my changes.
• I added/updated integration tests for my changes.
• I ran the integration tests.
• I tested my changes in Node, Deno, and the browser.
• I viewed documents produced with my changes in Adobe Acrobat, Foxit Reader, Firefox, and Chrome.
• I added/updated doc comments for any new/modified public APIs.
• My changes work for both new and existing PDF files.
• I ran the linter on my changes.

[Sharcoux]

Thanks a lot! Nice catch.