[lib] Introduce isValidSIWEStatementWithPublicKey(...)

Summary:
Introduce isValidSIWEStatementWithPublicKey(...) to check if SIWE statement is valid statement that includes the Device IdPubKey as described in the whitepaper: https://blob.sh/a3d138.png

Depends on D6129

Test Plan: included a unit test (will include more later)

Reviewers: ashoat, tomek

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D6130