Tests

Bump third_party/openthread/repo from `287dbfa` to `e43120d` #1042

Job	Run time
REPL Tests - Darwin	0s
REPL Tests - Linux	1h 38m 33s
Test Suites - Darwin (no-ble-no-shell-asan-clang)	1h 22m 54s
Test Suites - Linux (no-ble-no-shell-tsan-clang)	1h 58m 17s
Test Suites - Darwin (no-ble-no-shell-tsan-clang)	1h 55m 33s
	6h 55m 17s

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