Add crossOrigin property to <img> tag used for decoding

[harryterkelsen]

Adds the crossOrigin property to the <img> tag used for decoding. This allows us to use cross-origin images in CanvasKit as if it were loaded from the same origin, as long as the CORS headers are properly set on the server hosting the image.

In the case where the image doesn't have proper CORS headers, this change causes an error to occur while attempting to decode, rather than later on in Skia when the image is converted into a texture. Hitting the cross-origin error later causes Skia to behave in undefined ways.

Progress towards flutter/flutter#149843

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[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!).

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group.

[yjbanov]

Is this testable? LGTM otherwise.

[jacobsimionato]

Can we roll this change back? It broke a customer using the HTML renderer in google3 - see flutter/flutter#154809 and b/365475814

[auto-submit]

Time to revert pull request flutter/engine/54961 has elapsed.
You need to open the revert manually and process as a regular pull request.

[eyebrowsoffire]

Created a manual revert here: #55042