Fix network settings crash on Android

Register AIRPLANE_MODE setting in settingsItems map and add missing
string resources to prevent crashes when opening network options.

Signed-off-by: Zephyron <zephyron@citron-emu.org>

src/android/app/src/main/java/org/citron/citron_emu/features/settings/model/view/SettingsItem.kt

@@ -615,6 +615,15 @@ abstract class SettingsItem(
                     valuesId = R.array.appletModeValues
                 )
             )
+
+            // Network Settings
+            put(
+                SwitchSetting(
+                    BooleanSetting.AIRPLANE_MODE,
+                    titleId = R.string.airplane_mode,
+                    descriptionId = R.string.airplane_mode_description
+                )
+            )
         }
     }
 }

src/android/app/src/main/res/values/strings.xml

@@ -430,6 +430,8 @@
 
     <!-- Network Settings Headers -->
     <string name="network_settings_header">Network Settings</string>
+    <string name="airplane_mode">Airplane Mode</string>
+    <string name="airplane_mode_description">Disable all network functionality, similar to Nintendo Switch airplane mode</string>
 
     <!-- Zep Zone Headers -->
     <string name="memory_layout_header">Memory Layout</string>