Continue on adding ECDSA support to WebCrypto API. This patch implements
verify operation of ECDSA, using ECDSA implementation from the crates
`ecdsa` for the operation, `p256`, `p384`, `p521`, and `elliptic_curve`
for the key, and `sha1`, `sha2` and `digest` for digesting messages.
Testing: Pass some WPT tests that were expected to fail.
Fixes: Part of #39060
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Signed-off-by: Kingsley Yung <kingsley@kkoyung.dev>