ui: reset disksize param on offering change in scale vm (#6636)

Fixes #6627

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

Author: shwstppr

ui/src/views/compute/ScaleVM.vue

@@ -217,6 +217,7 @@ export default {
       delete this.params[this.cpuNumberKey]
       delete this.params[this.cpuSpeedKey]
       delete this.params[this.memoryKey]
+      delete this.params[this.rootDiskSizeKey]
 
       this.params.serviceofferingid = id
       this.selectedOffering = this.offeringsMap[id]