perf: use less promises in extractBody #16801

Job	Run time
Lint	37s
dependency-review	12s
Test with Node.js 24 compiled --without-intl	6m 22s
Test with Node.js 20 compiled --without-intl	6m 47s
Test with SQLite enabled	29s
Test with Node.js 22 compiled --without-intl	6m 26s
Fuzzing	3m 48s
Test TypeScript types	50s
test (22, windows-latest) / Test with Node.js 22 on windows-latest	6m 13s
test (20, ubuntu-latest) / Test with Node.js 20 on ubuntu-latest	5m 4s
test (22, macos-latest) / Test with Node.js 22 on macos-latest	4m 33s
test (24, windows-latest) / Test with Node.js 24 on windows-latest	5m 45s
test (22, ubuntu-latest) / Test with Node.js 22 on ubuntu-latest	5m 12s
test (24, ubuntu-latest) / Test with Node.js 24 on ubuntu-latest	4m 36s
test (24, macos-latest) / Test with Node.js 24 on macos-latest	4m 20s
test (20, macos-latest) / Test with Node.js 20 on macos-latest	5m 46s
automerge	0s
	1h 7m 0s

Provide feedback