Consolidate signature-status rpcs (#9069)

* getSignatureStatus: return confirmations for non-rooted transactions

* Remove getNumConfirmations.. rpc

* Remove getSignatureConfirmation

* Review comments

* More review comments

client/src/mock_rpc_client_request.rs

@@ -101,9 +101,16 @@ impl GenericRpcClientRequest for MockRpcClientRequest {
                 let status = if self.url == "sig_not_found" {
                     None
                 } else {
-                    Some(TransactionStatus { status, slot: 1 })
+                    Some(TransactionStatus {
+                        status,
+                        slot: 1,
+                        confirmations: Some(0),
+                    })
                 };
-                serde_json::to_value(vec![status])?
+                serde_json::to_value(Response {
+                    context: RpcResponseContext { slot: 1 },
+                    value: vec![status],
+                })?
             }
             RpcRequest::GetTransactionCount => Value::Number(Number::from(1234)),
             RpcRequest::GetSlot => Value::Number(Number::from(0)),