L3: isUnlocked() returns false when no active connection

Previously always returned true. Now returns true only when the site
has been approved via eth_requestAccounts (selectedAddress is set).

src/content/inpage.js

@@ -134,7 +134,7 @@
         // Some dApps (wagmi) check this to confirm MetaMask-like behavior
         _metamask: {
             isUnlocked() {
-                return Promise.resolve(true);
+                return Promise.resolve(provider.selectedAddress !== null);
             },
         },
     };