In BF-26175 an FLE2 transaction which started on a server could not be completed because primary was switched during transaction

This is for security team to evaluate possible ways of handling the scenario:

• handle inside test (no value really)
• handle inside mongo-shell (also not a lot of value, because of legacy nature of mongo shell)
• have primary hand-off transaction to secondary on switch. will only work if primary gracefully hands off primary function
• delay primary switch until fle2 transaction completes. Same consideration as above