feat: removes use of date in nonce generation

[krpeacock]

Description

Replace use of date in nonce generation

Checklist:

• My changes follow the guidelines in CONTRIBUTING.md.
• The title of this PR complies with Conventional Commits.
• I have edited the CHANGELOG accordingly.
• I have made corresponding changes to the documentation.

[github-actions]

size-limit report 📦

Path	Size
@dfinity/agent	89.16 KB (-0.06% 🔽)
@dfinity/candid	15.48 KB (0%)
@dfinity/principal	6.77 KB (0%)
@dfinity/auth-client	94.89 KB (0%)
@dfinity/assets	91.7 KB (0%)
@dfinity/identity	91.96 KB (0%)
@dfinity/identity-secp256k1	230.5 KB (-0.02% 🔽)