fix(webgl): Fix webglAdapter.attach()

[ibgreen]

For #2295

Background

• Fix interleaved canvas creation deck.gl#9285

Change List

• Looks like the code path to attach to existing context had been lost during succession of refactors.
• Also added CanvasContext creation and autoResize prevention.

[Pessimistress]

Should this apply to 9.1-release as well? (Instead of #2297)

[ibgreen]

Should this apply to 9.1-release as well? (Instead of #2297)

Only if we see a need, I prefer to make minimal changes on the non-master branches. These parts of the code have been changing so there is a risk of having to debug twice or bring in more changes to 9.1.

Also the delta between master and 9.1 is bigger now after @felixpalmer reverted 9.1. changes to get luma 9.1 working in deck.gl test suite.