improve: set up provider url as default network

packages/app/src/systems/DApp/services/FuelProviderService.ts

@@ -3,21 +3,30 @@ import { Provider } from 'fuels';
 class _FuelProviderService {
   private providers: Record<string, Provider> = {};
 
+  constructor() {
+    //@TODO: Make this a sync instantiation once we upgrade to SDK 0.98.0
+    import.meta.env.VITE_FUEL_PROVIDER_URL &&
+      this.getOrUpdateProvider(import.meta.env.VITE_FUEL_PROVIDER_URL);
+  }
+
   async createProvider(providerUrl: string) {
     this.providers[providerUrl] = await Provider.create(providerUrl);
     return this.providers[providerUrl];
   }
 
   getProvider(providerUrl: string | undefined) {
     if (!providerUrl) {
-      throw new Error('FuelProviderService: Provider URL is required');
+      return undefined;
     }
     return this.providers[providerUrl];
   }
 
   async getOrUpdateProvider(providerUrl: string | undefined) {
     if (!providerUrl) {
-      throw new Error('FuelProviderService: Provider URL is required');
+      return (
+        this.providers[import.meta.env.VITE_FUEL_PROVIDER_URL] ||
+        this.providers[Object.keys(this.providers)?.[0]]
+      );
     }
     if (this.providers[providerUrl]) {
       return this.providers[providerUrl];