fix: skip serializing functions returned by exported functions during pause

[nynevi]

Overview:

Prevents serializing functions that return other functions which otherwise yields in error Only primitive and object literals can be serialized:

Fixes #4371

Checklist:

• My code follows the developer guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• Added new tests to cover the fix / functionality

[stackblitz]

Run & review this pull request in StackBlitz Codeflow.

[netlify]

👷 Deploy request for qwik-insights pending review.

Visit the deploys page to approve it

Name	Link
🔨 Latest commit	4fb9752

[mhevery]

Thank you for your contribution; unfortunately, I don't think this is the correct fix.

1. This fix silently ignores function values during serialization and deserializes them as undefined This will cause a surprise in the browser. The correct behavior is to tell the developer that they have made a mistake.

• There should be a clear runtime error (instead of the current cryptic error)
• The linter should be updated to underline the offending code correctly.

2. We need to have tests with the change.

[gioboa]

@nynevi thanks for opening this PR.
I'm closing this for now because it's stale, feel free to create a new PR with your improvements. 💪