remove superfluous (IMO) strings

app/src/main/java/de/westnordost/streetcomplete/quests/opening_hours/AddOpeningHoursForm.java

@@ -10,7 +10,6 @@
 import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.EditText;
-import android.widget.Toast;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -173,8 +172,8 @@ private void showConfirm24_7Dialog()
 	private void confirmNoSign()
 	{
 		new AlertDialogBuilder(getActivity())
-			.setTitle(R.string.quest_openingHours_answer_noSign_confirmation_title)
-			.setPositiveButton(R.string.quest_openingHours_noSign_confirmation_positive, (dialog, which) ->
+			.setTitle(R.string.quest_generic_confirmation_title)
+			.setPositiveButton(R.string.quest_generic_confirmation_yes, (dialog, which) ->
 			{
 				Bundle data = new Bundle();
 				data.putBoolean(NO_SIGN, true);

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

@@ -456,8 +456,6 @@ Otherwise, you can download another keyboard in the app store. Popular keyboards
     <string name="invalidation_dialog_message">Invalidating the cache causes the quests to be updated next time they are downloaded. The quest cache is invalidated automatically after one week and immediately when a quest you solved turns out to be already answered by someone else.</string>
     <string name="quest_openingHours_emptyAnswer">You need to describe what is on the sign. If there is no sign, you should ask for the opening hours inside.</string>
     <string name="quest_openingHours_no_sign">No opening hours sign</string>
-    <string name="quest_openingHours_answer_noSign_confirmation_title">Are you sure that there is no sign with opening hours info?</string>
-    <string name="quest_openingHours_noSign_confirmation_positive">Yes, no sign.</string>
     <string name="quest_cycleway_value_none_but_no_oneway">none, but cyclists may use road in both directions</string>
     <string name="quest_generic_looks_like_this">Usually looks like this:</string>
     <string name="quest_surface_value_metal">Metal</string>