i18n: restore key parity after the Jalali calendar

The translation parity test fails on main again after the Jalali
calendar landed: the two newest locales, he and sk, were missed when
the twelve Jalali month names were added - they get the same Latin
transliterations every other non-Persian locale received.

fa in turn carried four keys that do not exist in en and are not
referenced anywhere in the code (the email_composer.text_direction
block and settings.templates.image_too_large) - removed, as the
suite's no-extra-keys check demands.

locales/sk/common.json

@@ -2723,7 +2723,19 @@
       "sep": "sep",
       "oct": "okt",
       "nov": "nov",
-      "dec": "dec"
+      "dec": "dec",
+      "far": "Farvardin",
+      "ord": "Ordibehesht",
+      "kho": "Khordad",
+      "tir": "Tir",
+      "mor": "Mordad",
+      "sha": "Shahrivar",
+      "meh": "Mehr",
+      "aba": "Aban",
+      "aza": "Azar",
+      "dey": "Dey",
+      "bah": "Bahman",
+      "esf": "Esfand"
     },
     "notifications": {
       "event_created": "Udalosť bola vytvorená",