Add alt text validation option to user preferences (supersedes #913) (#914)

* Add alt text validation option to user preferences

* Fix typos/linting issues

* Update accessibility setting to match styles

* Update the required alt text reminder to go away once it's added

---------

Co-authored-by: Emma Fuller <emma@emmafuller.dev>

src/view/screens/Settings.tsx

@@ -330,6 +330,22 @@ export const SettingsScreen = withAuthRequired(
           </TouchableOpacity>
 
           <View style={styles.spacer20} />
+
+          <Text type="xl-bold" style={[pal.text, styles.heading]}>
+            Accessibility
+          </Text>
+          <View style={[pal.view, styles.toggleCard]}>
+            <ToggleButton
+              type="default-light"
+              label="Require alt text on images"
+              labelType="lg"
+              isSelected={store.preferences.requireAltTextEnabled}
+              onPress={store.preferences.toggleRequireAltTextEnabled}
+            />
+          </View>
+
+          <View style={styles.spacer20} />
+
           <Text type="xl-bold" style={[pal.text, styles.heading]}>
             Appearance
           </Text>
@@ -633,6 +649,11 @@ const styles = StyleSheet.create({
     paddingHorizontal: 18,
     marginBottom: 1,
   },
+  toggleCard: {
+    paddingVertical: 8,
+    paddingHorizontal: 6,
+    marginBottom: 1,
+  },
   avi: {
     marginRight: 12,
   },