Remove the lock from ShardSplitDonorService::DonorStateMachine::checkIfOptionsConflict. Create const member fields like tenant_migration_donor_service (https://github.com/10gen/mongo/blob/103cf67c1488288beb7d8bd68f3550a612d6d054/src/mongo/db/repl/tenant_migration_donor_service.h#L288-L296) so lock is not needed to check options.

Change is aimed to avoid deadlock when:

(1) Instance lock is held in ShardSplitDonorService::DonorStateMachine::run (https://github.com/10gen/mongo/blob/9743d69c7dbc92fd5abcf9c799daff89e30ca233/src/mongo/db/serverless/shard_split_donor_service.cpp#L335)

(2) POS lock is held ShardSplitDonorService::getOrCreateInstance (https://github.com/10gen/mongo/blob/9743d69c7dbc92fd5abcf9c799daff89e30ca233/src/mongo/db/repl/primary_only_service.cpp#L543)

(3) getOrCreateInstance -> ShardSplitDonorService::DonorStateMachine::checkIfOptionsConflict waits on instance lock (https://github.com/10gen/mongo/blob/9743d69c7dbc92fd5abcf9c799daff89e30ca233/src/mongo/db/serverless/shard_split_donor_service.cpp#L295) 

(2) onCreateOperationContext -> ShardSplitDonorService::registerOpCtx waits on POS lock (https://github.com/10gen/mongo/blob/9743d69c7dbc92fd5abcf9c799daff89e30ca233/src/mongo/db/repl/primary_only_service.cpp#L261).