UI: Fix VNF NIC mapping network select always disabled

Remove incorrect disabled attribute from VnfNicsSelection.vue.
The attribute was a plain string instead of Vue binding, causing
the select to always be disabled regardless of state.

Author: Gia-Bursulaia

ui/src/views/compute/wizard/VnfNicsSelection.vue

@@ -50,7 +50,6 @@
       <template #network="{ record }">
         <a-form-item style="display: block" :name="'nic-' + record.deviceid">
           <a-select
-            disabled="templateNics && templateNics.length > 0"
             @change="updateNicNetworkValue($event, record.deviceid)"
             optionFilterProp="label"
             :filterOption="(input, option) => {