fix(l10n): repair corrupted duration abbreviations in ar/bn/hi/ja/ru/zh ARB files

Sleep-timer duration strings (durationHoursMinutesSeconds, durationMinutesSeconds,
durationMinutesOnly, durationSecondsOnly) contained literal "?" characters instead
of the native hour/minute/second abbreviation in 6 locales. Replaced with correct
native short-form units per locale, verified byte-exact against a pinned spec table
and against the already-correct neighboring hoursLabel/minutesLabel/secondsLabel
values in each file.

lib/l10n/app_bn.arb

@@ -16,7 +16,7 @@
   "hoursLabel": "ঘণ্টা",
   "minutesLabel": "মিনিট",
   "secondsLabel": "সেকেন্ড",
-  "durationHoursMinutesSeconds": "{hours} ? {minutes} ?? {seconds} ??",
+  "durationHoursMinutesSeconds": "{hours} ঘণ্টা {minutes} মিনিট {seconds} সেকেন্ড",
   "@durationHoursMinutesSeconds": {
     "placeholders": {
       "hours": {},
@@ -24,20 +24,20 @@
       "seconds": {}
     }
   },
-  "durationMinutesSeconds": "{minutes} ?? {seconds} ??",
+  "durationMinutesSeconds": "{minutes} মিনিট {seconds} সেকেন্ড",
   "@durationMinutesSeconds": {
     "placeholders": {
       "minutes": {},
       "seconds": {}
     }
   },
-  "durationMinutesOnly": "{minutes} ??",
+  "durationMinutesOnly": "{minutes} মিনিট",
   "@durationMinutesOnly": {
     "placeholders": {
       "minutes": {}
     }
   },
-  "durationSecondsOnly": "{seconds} ??",
+  "durationSecondsOnly": "{seconds} সেকেন্ড",
   "@durationSecondsOnly": {
     "placeholders": {
       "seconds": {}