fix: Fix issues on Firefox mobile

Author: marienfressinaud

src/screens/LinkScreen.vue

@@ -221,5 +221,7 @@ onMounted(refreshCurrentTabUrl);
 
 browser.tabs.onUpdated.addListener(refreshCurrentTabUrl);
 browser.tabs.onActivated.addListener(refreshCurrentTabUrl);
-browser.windows.onFocusChanged.addListener(refreshCurrentTabUrl);
+if (browser.windows) {
+    browser.windows.onFocusChanged.addListener(refreshCurrentTabUrl);
+}
 </script>

src/screens/MenuScreen.vue

@@ -67,7 +67,9 @@ async function openShortcuts() {
 const shouldShowShortcuts = ref(false);
 
 onMounted(async () => {
-    shouldShowShortcuts.value =
-        (await browserUtils.isChrome()) || browser.commands.openShortcutSettings != null;
+    const isChrome = await browserUtils.isChrome();
+    const hasShortcutCommand = browser.commands && browser.commands.openShortcutSettings != null;
+
+    shouldShowShortcuts.value = isChrome || hasShortcutCommand;
 });
 </script>