Check for Canvas API before using instead of environment

[korywka]

Issue: #1372

The IS_WEBWORKER_ENV is true for Deno Worker runtime:

transformers.js/src/env.js

Line 33 in 699dcb5

const IS_WEBWORKER_ENV = typeof self !== "undefined" && (['DedicatedWorkerGlobalScope', 'ServiceWorkerGlobalScope', 'SharedWorkerGlobalScope'].includes(self.constructor?.name));

So it is not reliable condition to check for HTML/Offscreen-Canvas API usage.

One way to fix it is to go from env-based conditions to feature-based.

If we add Deno condition to exclude Canvas API, it would work for now, but I think it will be broken for Node Workers (nodejs/node#43583) and Bun Web Workers.

Please note that this PR has been tested only with Deno, not other environments. It should be tested further, closed, or used as a starting point.