fix: ObservableLog no longer extends Function

[krpeacock]

Description

Funded app reported that in Chrome browser extensions, the Function / Proxy implementation was being rejected under rules blocking the use of eval.

How Has This Been Tested?

Once Funded has tested the changes in their extension, this can be merged

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	85.8 KB (-0.12% 🔽)
@dfinity/candid	13.58 KB (0%)
@dfinity/principal	4.97 KB (0%)
@dfinity/auth-client	60.8 KB (-0.06% 🔽)
@dfinity/assets	80.5 KB (-0.05% 🔽)
@dfinity/identity	58 KB (-0.1% 🔽)
@dfinity/identity-secp256k1	266.21 KB (-0.04% 🔽)

[mzibara]

Approved on PLUG side, thank you!