fix: measure individual call durations in sequential phase of concurrency decorator #288

Job	Run time
determine-changes / detect	12s
check-linked-issue	3s
type-check	29s
coverage	7m 14s
unit-tests (ubuntu-latest, 3.10)	7m 48s
unit-tests (ubuntu-latest, 3.14)	6m 47s
unit-tests (ubuntu-latest, 3.12)	6m 32s
unit-tests (ubuntu-latest, 3.11)	6m 55s
e2e-python (futurehouse-structure, end_to_end_test_futurehouse.py, 5)	2m 32s
prek / prek	28s
unit-tests (windows-latest, 3.13)	7m 57s
e2e-python (tracer-replay, end_to_end_test_tracer_replay.py, 10)	5m 36s
unit-tests (ubuntu-latest, 3.13)	7m 35s
e2e-python (benchmark-bubble-sort, end_to_end_test_benchmark_sort.py, 5)	7m 49s
unit-tests (ubuntu-latest, 3.9)	7m 49s
e2e-python (topological-sort, end_to_end_test_topological_sort_worktree.py, 5)	2m 56s
e2e-python (bubble-sort-pytest-nogit, end_to_end_test_bubblesort_pytest.py, 70, true)	7m 52s
e2e-python (bubble-sort-unittest, end_to_end_test_bubblesort_unittest.py, 40)	7m 50s
e2e-python (init-optimization, end_to_end_test_init_optimization.py, 10)	2m 32s
e2e-python (async-optimization, end_to_end_test_async.py, 10)	3m 24s
e2e-python (coverage-e2e, end_to_end_test_coverage.py, black)	5m 53s
e2e-js	-1s
e2e-java	-1s
required checks passed	3s
	1h 46m 14s

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