[yugabyte#7024] Platform: Fixed edit number of nodes in AZ section (yugabyte#7029)

Description: The user was not able to edit the numbers of nodes from the AZ section while editing the universe. The issue was due to an undefined variable on the initial rendering. Added the API call to set the context for the number of nodes in the AZ section.

Test scenario: Able to modify the number of nodes from the AZ section while editing the universe.

Author: gaurav061

managed/ui/src/components/universes/UniverseForm/AZSelectorTable.js

@@ -113,7 +113,7 @@ export default class AZSelectorTable extends Component {
     } = this.props;
     const universeTemplate = _.clone(universeConfigTemplate.data);
     const currentAZState = [...this.state.azItemState];
-    const replicationFactor = currentPlacementStatus.replicationFactor;
+    const replicationFactor = currentPlacementStatus?.replicationFactor;
     const item = currentAZState.find(item => item.value === zoneId);
     const originalValue = item.count;
     let totalNumNodes = 0;
@@ -403,10 +403,24 @@ export default class AZSelectorTable extends Component {
 
   UNSAFE_componentWillMount() {
     const {
-      universe: { currentUniverse, universeConfigTemplate },
+      universe: { currentUniverse, universeConfigTemplate, currentPlacementStatus},
       type,
       clusterType
     } = this.props;
+
+    // If currentPlacementStatus is null the fetch it.
+    if(!currentPlacementStatus) {
+      const configTemplateCurrentCluster = isNonEmptyObject(universeConfigTemplate.data)
+        ? getClusterByType(universeConfigTemplate.data.clusters, clusterType)
+        : null;
+      const placementInfo = this.getGroupWithCounts(universeConfigTemplate.data);
+      const placementStatusObject = {
+        numUniqueRegions: placementInfo.uniqueRegions,
+        numUniqueAzs: placementInfo.uniqueAzs,
+        replicationFactor: configTemplateCurrentCluster.userIntent.replicationFactor
+      };
+      this.props.setPlacementStatus(placementStatusObject);
+    }
     const currentCluster = getPromiseState(universeConfigTemplate).isSuccess()
       ? getClusterByType(universeConfigTemplate.data.clusters, clusterType)
       : {};
@@ -434,7 +448,7 @@ export default class AZSelectorTable extends Component {
       const placementInfo = this.getGroupWithCounts(universeConfigTemplate.data);
       const azGroups = placementInfo.groups;
       if (
-        !areUniverseConfigsEqual(
+        !areUniverseConfigsEqual( 
           this.props.universe.universeConfigTemplate.data,
           universeConfigTemplate.data
         )

managed/ui/src/components/universes/UniverseForm/ClusterFields.js

@@ -1591,7 +1591,7 @@ export default class ClusterFields extends Component {
         <AZPlacementInfo
           placementInfo={self.props.universe.currentPlacementStatus}
           placementCloud={placementCloud}
-          providerCode={currentProvider.code}
+          providerCode={currentProvider?.code}
         />
       );
     } else if (currentProvider?.code === 'onprem'