Fix bug on custom polygon shape with border

[tomerv]

Resolve #3413 by skipping miter calculations for custom polygon shapes

Cross-references to related issues.

Associated issues:

• Bug when using polygon shape #3413

Notes re. the content of the pull request.

• This PR skips the miter calculations for custom polygon shapes. It's not a full solution to the original issue (Rendered angled node shapes with large borders are cut off at specific zoom levels. #3382) but it's much better than the current situation where the render completely fails.

Checklist

Author:

• The proper base branch has been selected. New features go on unstable. Bug-fix patches can go on either unstable or master.
• Automated tests have been included in this pull request, if possible, for the new feature(s) or bug fix. Check this box if tests are not pragmatically possible (e.g. rendering features could include screenshots or videos instead of automated tests).
• The associated GitHub issues are included (above).
• Notes have been included (above).
• For new or updated API, the index.d.ts Typescript definition file has been appropriately updated.

Reviewers:

• All automated checks are passing (green check next to latest commit).
• At least one reviewer has signed off on the pull request.
• For bug fixes: Just after this pull request is merged, it should be applied to both the master branch and the unstable branch. Normally, this just requires cherry-picking the corresponding merge commit from master to unstable -- or vice versa.

[tomerv]

@maxkfranz , can you please help here? How can I get this merged? The bug completely breaks Cytoscape.js without any clear error indicating the cause, and this PR fixes the issue.