feat: Faster JSON dumps in `format_message` with `msgspec` #3789

Job	Run time
Test on 3.7 (tests) / ubuntu-latest / SQLAlchemy: 2.*	38s
Test on 3.8 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 22s
Test on 3.9 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 14s
Test on 3.10 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 9s
Test on 3.11 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 16s
Test on 3.7 (tests) / macos-latest / SQLAlchemy: 2.*	57s
Test on 3.8 (tests) / macos-latest / SQLAlchemy: 2.*	2m 13s
Test on 3.9 (tests) / macos-latest / SQLAlchemy: 2.*	2m 14s
Test on 3.10 (tests) / macos-latest / SQLAlchemy: 2.*	2m 8s
Test on 3.11 (tests) / macos-latest / SQLAlchemy: 2.*	2m 13s
Test on 3.7 (tests) / windows-latest / SQLAlchemy: 2.*	1m 21s
Test on 3.8 (tests) / windows-latest / SQLAlchemy: 2.*	3m 43s
Test on 3.9 (tests) / windows-latest / SQLAlchemy: 2.*	2m 24s
Test on 3.10 (tests) / windows-latest / SQLAlchemy: 2.*	2m 57s
Test on 3.11 (tests) / windows-latest / SQLAlchemy: 2.*	2m 35s
Test on 3.11 (tests) / ubuntu-latest / SQLAlchemy: 1.*	1m 19s
Test on 3.10 (doctest) / ubuntu-latest / SQLAlchemy: 2.*	37s
Test on 3.8 (mypy) / ubuntu-latest / SQLAlchemy: 2.*	1m 1s
External Tests	0s
Coverage	0s
	31m 21s

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