Replace last hard-coded string

Also, add a few words to the dictionary and remove an unused string

.idea/dictionaries/briar.xml

 <component name="ProjectDictionaryState">
   <dictionary name="briar">
     <words>
+      <w>addr</w>
       <w>affero</w>
       <w>agpl</w>
       <w>briar</w>
       <w>briarproject</w>
+      <w>dnkm</w>
+      <w>dontkillme</w>
       <w>obfs</w>
       <w>onboarding</w>
+      <w>unicast</w>
     </words>
   </dictionary>
 </component>

mailbox-android/src/main/res/layout/fragment_setup_complete.xml

@@ -55,7 +55,7 @@
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_margin="16dp"
-        android:text="Finish"
+        android:text="@string/setup_complete_finish"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent" />

mailbox-android/src/main/res/values/strings.xml

@@ -37,8 +37,8 @@
 
     <string name="no_network_title">Device offline?</string>
     <string name="no_network_description">Please ensure this device is online and connected to the Internet. Once you\'re online, setup should pick up automatically here.</string>
-    <string name="no_network_try_again">Try again</string>
 
     <string name="setup_complete_title">Connected</string>
     <string name="setup_complete_description">Your Mailbox has been successfully linked with Briar.\n\nKeep your Mailbox connected to power and Wi-Fi so it\'s always online.</string>
+    <string name="setup_complete_finish">Finish</string>
 </resources>