[BUG]: selectedpoints for curvenumber > 0 invisible when using scattergl

[ismirsehregal]

Description

When setting selectedpoints on a scattergl trace for curvenumbers > 0, the markers disappear - for curvenumber 0 it works as expected.

Screenshots/Video

Works as expected:
var curveNumber = 0;
var selected = [0, 1, 2];

Selected markers disappear:
var curveNumber = 1;
var selected = [0, 1, 2];

Steps to reproduce

Please switch between curveNumber = 0 and curveNumber = 1

https://codepen.io/ismirsehregal/pen/gbwgOWm

Notes

Error messages in the browser console:

(index):1 [.WebGL-0x25640015b100] GL_INVALID_OPERATION: Error: 0x00000502, in ....\third_party\angle\src\libANGLE\renderer\renderer_utils.cpp, rx::ComputeStartVertex:1591. Internal error: 0x00000502: Integer overflow.
(index):1 [.WebGL-0x25640015b100] GL_INVALID_OPERATION: Error: 0x00000502, in ....\third_party\angle\src\libANGLE\renderer\d3d\VertexDataManager.cpp, rx::VertexDataManager::reserveSpaceForAttrib:535. Internal error: 0x00000502: Vertex buffer is not big enough for the draw call.

I posted the issue here first. However, this seems to be a plotly.js bug.
This might be related.

[camdecoster]

Thanks for the excellent bug report! Our team will try to take a look into this, but it might take a while. In the meantime, if you want to take a crack at fixing it, we could prioritize a PR review.