Upgrade Internet Identity Backend Canister to 21ab317d3

Backend Canister Upgrade

What's Changed

_Since proposal-backend-143472_

• fix(be): pin AuthorizationKey on email challenges and drop pending on… (#4195)
• fix(fe,be): three papercuts found triaging intermittent OpenID sign-ins (#4213)
• fix(be,fe): base the Settings MCP config on the certified identity_info (#4215)
• test(be): regression coverage for DKIM From-header forgery in email recovery (#4209)
• fix(be): reject email addresses containing more than one @ (#4208)

Full release notes

Wasm Verification

To build the wasm modules yourself and verify their hashes, run the following commands from the root of the Internet Identity repository:

git pull  # to ensure you have the latest changes.
git checkout 21ab317d3bf27467336c902702bfd41b0f4ea06e
./scripts/verify-hash --ii-hash fd51df0366bff3e3dae13eadc3baa5f228397dfc49a7ee3b1e7c6683908625ea

Backend Argument Verification

Run the following command to verify the backend upgrade argument hash:

didc encode -d ./src/internet_identity/internet_identity.did -t '(opt InternetIdentityInit)' '(null)' | xxd -r -p | sha256sum

The output should match the argument hash.