Fix optional bodies #3141

Job	Run time
test_min_deps (ubuntu-latest)	46s
test_min_deps (macos-latest)	1m 17s
Integration Tests (pdm.minimal.lock)	28s
test_min_deps (windows-latest)	1m 25s
Integration Tests (pdm.lock)	31s
test (3.11, ubuntu-latest)	1m 2s
test (3.10, ubuntu-latest)	1m 11s
test (3.11, windows-latest)	2m 2s
test (3.12, macos-latest)	48s
test (3.10, macos-latest)	1m 3s
test (3.10, windows-latest)	1m 27s
test (3.12, ubuntu-latest)	1m 11s
test (3.13, ubuntu-latest)	1m 8s
test (3.14, ubuntu-latest)	1m 2s
test (3.13, windows-latest)	1m 36s
test (3.11, macos-latest)	52s
test (3.13, macos-latest)	50s
test (3.14, windows-latest)	1m 43s
test (3.12, windows-latest)	1m 45s
test (3.14, macos-latest)	1m 25s
Combine & check coverage	17s
	23m 49s

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