Tests

Bump third_party/imgui/repo from `3c435c0` to `aa23f38` #6070

Job	Run time
Test Suites - Linux (no-ble-no-shell-tsan-clang)	2h 0m 27s
REPL Tests - Darwin	0s
REPL Tests - Linux	1h 35m 27s
Test Suites - Darwin (no-ble-no-shell-asan-clang)	1h 34m 28s
Test Suites - Darwin (no-ble-no-shell-tsan-clang)	2h 1m 59s
	7h 12m 21s

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