Bump third_party/ot-br-posix/repo from `ff2f24c` to `03132d3` #1356

Job	Run time
REPL Tests - Linux	28m 23s
Test Suites - Darwin (no-ble-asan-clang)	1h 38m 3s
Test Suites - Darwin (no-ble-tsan-clang)	2h 8m 56s
Test Suites - Linux (no-ble-tsan-clang)	1h 19m 55s
REPL Tests - Darwin	0s
	5h 35m 17s

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