Bump third_party/imgui/repo from `ce13f6b` to `2737dbb` #760

Job	Run time
REPL Tests - Linux	2h 6m 57s
Test Suites - Darwin (no-ble-no-shell-asan-clang)	1h 37m 55s
Test Suites - Linux (no-ble-no-shell-tsan-clang)	1h 51m 2s
Test Suites - Darwin (no-ble-no-shell-tsan-clang)	1h 58m 54s
REPL Tests - Darwin	0s
	7h 34m 48s

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