Bump third_party/pigweed/repo from `1f12d06` to `aa6edfa` #2324

Job	Run time
Build on Linux (fake, gcc_release, clang, simulated)	1h 51m 2s
Build on Linux (gcc_debug)	1h 12m 33s
Build on Linux (python_lib)	2m 41s
Build on Darwin (clang, python_lib, simulated)	2m 35s
Build on Linux (coverage)	16m 51s
Build on Linux (python lighting-app)	3m 9s
	3h 28m 51s

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