Fix lock order inversion in promoteStakeContendersToTip

Summary:
Scheduler thread calls:
updatedBlockTip: cs_peerManager -> cs_main
promoteStakeContendersToTip: cs_stakeContendercache -> cs_peerManager

But main thread is calling addStakeContender: cs_main -> cs_stakeContenderCache

Swapping the lock order in promoteStakeContendersToTip fixes TSAN

Test Plan:

cmake -GNinja .. -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Debug -DENABLE_SANITIZERS=thread
ninja check-avalanche-processor_tests

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, Fabien

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D17058