Prevents "Device requesting login is not supported" for Flutter SDKs

[Ariflo]

• Adds jwt and rt attributes to Request and Response objects
• Adds DPop.dart to create JWT
• Fixes Error on login - "Device requesting login is not supported. Please try again from a secure context." #31

[shortcut-integration]

This pull request has been linked to Shortcut Story #84241: Integrate Webcrypto with our Flutter SDK.

[Ethella]

Could you audit the source code of the library to see if they are acutally getting the kp from Secure Enclave and key store. And make sure there is no malicious code in side?

[Ariflo]

Could you audit the source code of the library to see if they are acutally getting the kp from Secure Enclave and key store. And make sure there is no malicious code in side?

@Ethella this checks out, I would compare your code for iOS to their work here. Besides they're using SecKeyCreateRandomKey I don't see much of a difference.

Same goes for your Android work as compared to theirs.

With all of this in mind, I don't see any glaring security holes here, a second pair of 👀 would make me more confident. I'll touch base with MB on this and see if he has any tricks up his sleeves to help us confirm the validity of this library.