[FAB-15724] Improve migration integration test
[FAB-15724] Improve migration integration test

- Submits transactions using in-proc client instead of chaincode/peer
- Expand network to 2 nodes in solo->etcdraft migration test

Signed-off-by: Tiffany Harris <d1f145848d194a123b1c9e07ae428794bd7b9848@ibm.com>

muralisrini/fabric,stemlending/fabric,muralisrini/fabric,manish-sethi/fabric-sidedb,binhn/fabric,stemlending/fabric,binhn/fabric,manish-sethi/fabric-sidedb,binhn/fabric,manish-sethi/fabric-sidedb,hyperledger/fabric,hyperledger/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,jimthematrix/fabric,jimthematrix/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,manish-sethi/fabric,manish-sethi/fabric,manish-sethi/fabric-sidedb,stemlending/fabric