Bump third_party/pigweed/repo from `d5fcc90` to `85469bd` #1275

Job	Run time
REPL Tests - Darwin	0s
REPL Tests - Linux	12m 4s
Test Suites - Linux (no-ble-tsan-clang)	11m 17s
Test Suites - Darwin (no-ble-asan-clang)	2h 10m 3s
Test Suites - Darwin (no-ble-tsan-clang)	2h 15m 7s
	4h 48m 31s

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