Make edge bounds generation stricter
Make edge bounds generation stricter

- Make the use of `rstyle.bezierPts` and `rstyle.linePts` explicit to avoid potential problem cases where an edge curve style is changed.
- Make the reading of `rstyle.haystackPts` more guarded like other functions, such as `node.width()`.
- Apply fallback bounds only the instance is headless or if the instance has style disabled.

Ref : #2529 #2546

cytoscape/cytoscape.js,cytoscape/cytoscape.js