Change the placeholder to a country code that no other country uses. (#1491)

Co-authored-by: Vectorial1024

Author: youssefelzedy

data/fields/phone.json

@@ -6,7 +6,7 @@
     ],
     "type": "tel",
     "label": "Telephone",
-    "placeholder": "+31 42 123 4567",
+    "placeholder": "+000 0000 0000 0000",
     "terms": [
         "phone number"
     ]