feat: Faster JSON dumps in `format_message` with `msgspec` #3870

Job	Run time
Test on 3.7 (tests) / ubuntu-latest / SQLAlchemy: 2.*	33s
Test on 3.8 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 40s
Test on 3.9 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 40s
Test on 3.10 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 8s
Test on 3.11 (tests) / ubuntu-latest / SQLAlchemy: 2.*	1m 14s
Test on 3.7 (tests) / macos-latest / SQLAlchemy: 2.*	49s
Test on 3.8 (tests) / macos-latest / SQLAlchemy: 2.*	2m 9s
Test on 3.9 (tests) / macos-latest / SQLAlchemy: 2.*	2m 6s
Test on 3.10 (tests) / macos-latest / SQLAlchemy: 2.*	2m 14s
Test on 3.11 (tests) / macos-latest / SQLAlchemy: 2.*	2m 24s
Test on 3.7 (tests) / windows-latest / SQLAlchemy: 2.*	1m 21s
Test on 3.8 (tests) / windows-latest / SQLAlchemy: 2.*	3m 6s
Test on 3.9 (tests) / windows-latest / SQLAlchemy: 2.*	2m 56s
Test on 3.10 (tests) / windows-latest / SQLAlchemy: 2.*	4m 9s
Test on 3.11 (tests) / windows-latest / SQLAlchemy: 2.*	2m 53s
Test on 3.11 (tests) / ubuntu-latest / SQLAlchemy: 1.*	1m 11s
Test on 3.10 (doctest) / ubuntu-latest / SQLAlchemy: 2.*	42s
Test on 3.8 (mypy) / ubuntu-latest / SQLAlchemy: 2.*	1m 3s
External Tests	0s
Coverage	0s
	33m 18s

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