[canvaskit] Add dilate and erode imagefilters

[harryterkelsen]

Adds dilate and erode ImageFilters.

Fixes https://github.com/flutter/flutter/issues/101085

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• [x] I read the Contributor Guide and followed the process outlined there for submitting PRs.
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• [x] I listed at least one issue that this PR fixes in the description above.
• [x] I added new tests to check the change I am making or feature I am adding, or the PR is test-exempt. See testing the engine for instructions on writing and running engine tests.
• [x] I updated/added relevant documentation (doc comments with ///).
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• [x] All existing and new tests are passing.

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[harryterkelsen]

Thanks! PTAL

[flutter-dashboard[bot]]

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[flutter-dashboard[bot]]

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Changes reported for pull request #48553 at sha 916abf4dc650179a1f2eaf46cdda77e456a724e8