[canvaskit] Decode images using <img> tag decoding

[harryterkelsen]

Prefer to decode images using the browser API rather than with CanvasKit to avoid jank when decoding.

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[flutter-dashboard[bot]]

This pull request executed golden file tests, but it has not been updated in a while (20+ days). Test results from Gold expire after as many days, so this pull request will need to be updated with a fresh commit in order to get results from Gold.

[harryterkelsen]

This change causes the CanvasKit renderer to default to decoding using ImageDecoder when it's available, or using an ImageElement otherwise. To facilitate this, some helper methods were added which can read the pixels and resize ImageElement images using a DOM canvas, as a workaround to a bug in CanvasKit where getting pixel data from images created from textures returns an array of all 0s.

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Changes reported for pull request #53201 at sha e7aff4633b39ad7943a5a2d4a845adb0359b8968