Refactor wallet storage and subscription handling

- Updated WalletStore to manage localStorage and handle storage events more effectively.
- Introduced mockAccountsSubscribe in constants for better account subscription handling.
- Removed unnecessary storage subscription from InjectionConfig.
- Enhanced Wallet class to utilize new account and metadata management methods.

src/constants.ts

@@ -1,7 +1,7 @@
+import type { InjectedExtension } from "@polkadot/extension-inject/types";
+
 export const VARAN_WALLET_LS_KEY = 'VARAN_WALLET';
-
-
-window.addEventListener('storage', (ev) => {
-    if (ev.storageArea !== localStorage || ev.key !== VARAN_WALLET_LS_KEY) return;
-    
-})
+export const mockAccountsSubscribe: InjectedExtension['accounts']['subscribe'] = () => {
+    console.warn('Accounts subscribe does not currently support in Varan Wallet');
+    return () => {};
+};