Handle empty response from API listNetworkOfferings (#9)

Fix unhandled error when the response from API listNetworkOfferings is empty and causing TypeError on JS code.

This is to prevent a crash and showing pop up error window — If the API returns a response where listnetworkofferingsresponse has no networkoffering key (which happens when there are zero results — CloudStack omits empty arrays in JSON responses), the value would be undefined. The next line calls .filter() on it, which would throw TypeError: Cannot read properties of undefined (reading 'filter').

Author: manikonda

ui/src/views/network/CreateIsolatedNetworkForm.vue

@@ -551,7 +551,7 @@ export default {
       this.networkOfferings = []
       this.selectedNetworkOffering = {}
       getAPI('listNetworkOfferings', params).then(json => {
-        this.networkOfferings = json.listnetworkofferingsresponse.networkoffering
+        this.networkOfferings = json.listnetworkofferingsresponse.networkoffering || []
         this.networkOfferings = this.networkOfferings.filter(offering => offering.fornsx === this.selectedZone.isnsxenabled)
         if (!this.selectedZone.routedmodeenabled) {
           this.networkOfferings = this.networkOfferings.filter(offering => offering.networkmode !== 'ROUTED')