server: fix cannot update vm if it uses unconstraint dynamic offering (#7077)

Co-authored-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

engine/schema/src/main/java/com/cloud/service/ServiceOfferingVO.java

@@ -327,7 +327,7 @@ public class ServiceOfferingVO implements ServiceOffering {
     }
 
     public boolean isCustomCpuSpeedSupported() {
-        return isCustomized() && getDetail("minCPU") != null;
+        return isCustomized() && speed == null;
     }
 
     @Override