fix: fix imageRef for boot-from-volume instance

According to the api documentation, when the instance of bfv is created, imageRef does not need to be set, and it can be easily determined whether the instance is bfv based on this.

Change-Id: Ibacd417dd07a6cf8ee7d4d6dbd6b03cd5d0a5f99

src/pages/compute/containers/Instance/actions/StepCreate/index.jsx

@@ -592,7 +592,7 @@ export class StepCreate extends StepAction {
     if (this.enableCinder) {
       server.block_device_mapping_v2 = volumes;
     }
-    if (imageRef) {
+    if (imageRef && !volumes) {
       server.imageRef = imageRef;
     }
     if (loginType.value === 'keypair') {