Remove 'client_not_signed' layout from questionnaire logic

data/app_ui_strings.json

@@ -1,6 +1,6 @@
 {
     "version": 2,
-    "description": "Coach-visible app UI strings only (excludes dev settings \/ database tools).",
+    "description": "Coach-visible app UI strings only (excludes dev settings / database tools).",
     "keys": [
         "all_clients",
         "answer",
@@ -134,7 +134,7 @@
         "extreme_glass": "Extrem",
         "february": "Februar",
         "fill_all_fields": "Bitte alle Felder ausfüllen!",
-        "fill_both_fields": "Bitte beide Felder ausfüllen!",
+        "fill_both_fields": "Bitte Klienten-Code und Coach-Code prüfen.",
         "hours_short": "h",
         "january": "Januar",
         "july": "Juli",