Transaction retries don't work with multi-region clusters

[ianjevans]

During the MR Serverless bug-bash, the example throws a bunch of retry errors:

> node app.js

Initializing accounts table...
Transaction failed. Retrying transaction.
COMMIT; - restart transaction: TransactionRetryWithProtoRefreshError: TransactionRetryError: retry txn (RETRY_SERIALIZABLE - failed preemptive refresh due to a conflict: committed value on key /Tenant/41/Table/122/1/820164994132770838/0): "sql txn" meta={id=0a773ecd key=/Tenant/41/Table/3/1/123/2/1 pri=0.00085253 epo=0 ts=1670364898.635487399,2? min=1670364893.958771105,0 seq=5} lock=true stat=PENDING rts=1670364893.958771105,0 wto=false gul=1670364894.058771105,0
Transaction failed. Retrying transaction.
COMMIT; - restart transaction: TransactionRetryWithProtoRefreshError: TransactionRetryError: retry txn (RETRY_SERIALIZABLE - failed preemptive refresh due to a conflict: committed value on key /Tenant/41/Table/122/1/820164994132770838/0): "sql txn" meta={id=6cf9e379 key=/Tenant/41/Table/3/1/124/2/1 pri=0.02024304 epo=0 ts=1670364907.679461210,2? min=1670364903.890106411,0 seq=5} lock=true stat=PENDING rts=1670364903.890106411,0 wto=false gul=1670364903.990106411,0
Transaction failed. Retrying transaction.```

Wrapping the db init function in `retryTxn` didn't work. We need to investigate why the retry isn't working.