fix: update ChainSelector to handle chainId as a required number

Author: ErwanDecoster

src/components/navbar/ChainSelector.tsx

@@ -13,8 +13,8 @@ import {
 
 export function ChainSelector() {
   const { chainId } = useUserStore();
-  const [selectedChainId, setSelectedChainId] = useState<string | undefined>(
-    chainId?.toString()
+  const [selectedChainId, setSelectedChainId] = useState<string>(
+    chainId.toString(),
   );
 
   useEffect(() => {

src/stores/useUser.store.ts

@@ -12,8 +12,8 @@ type UserState = {
   setInitialized: (isInitialized: boolean) => void;
   address: Address | undefined;
   setAddress: (param: Address | undefined) => void;
-  chainId: number | undefined;
-  setChainId: (param: number | undefined) => void;
+  chainId: number;
+  setChainId: (param: number) => void;
   subgraphUrl: string;
   setSubgraphUrl: (param: string) => void;
 };
@@ -29,7 +29,7 @@ const useUserStore = create<UserState>((set) => ({
   setAddress: (address: Address | undefined) => {
     set({ address: address?.toLowerCase() as Address });
   },
-  chainId: undefined,
+  chainId: SUPPORTED_CHAINS[0].id,
   setChainId: (chainId: number | undefined) => {
     set({ chainId: chainId });
   },