Remove unnecessary null checks in flutter_localizations (#118863)

diff --git a/packages/flutter_localizations/lib/src/cupertino_localizations.dart b/packages/flutter_localizations/lib/src/cupertino_localizations.dart
index a07ddb9..7fec5fe 100644
--- a/packages/flutter_localizations/lib/src/cupertino_localizations.dart
+++ b/packages/flutter_localizations/lib/src/cupertino_localizations.dart
@@ -63,23 +63,14 @@
     required intl.DateFormat doubleDigitMinuteFormat,
     required intl.DateFormat singleDigitSecondFormat,
     required intl.NumberFormat decimalFormat,
-  }) : assert(localeName != null),
-       _localeName = localeName,
-       assert(fullYearFormat != null),
+  }) : _localeName = localeName,
        _fullYearFormat = fullYearFormat,
-       assert(dayFormat != null),
        _dayFormat = dayFormat,
-       assert(mediumDateFormat != null),
        _mediumDateFormat = mediumDateFormat,
-       assert(singleDigitHourFormat != null),
        _singleDigitHourFormat = singleDigitHourFormat,
-       assert(singleDigitMinuteFormat != null),
        _singleDigitMinuteFormat = singleDigitMinuteFormat,
-       assert(doubleDigitMinuteFormat != null),
        _doubleDigitMinuteFormat = doubleDigitMinuteFormat,
-       assert(singleDigitSecondFormat != null),
        _singleDigitSecondFormat = singleDigitSecondFormat,
-       assert(decimalFormat != null),
        _decimalFormat =decimalFormat;
 
   final String _localeName;
diff --git a/packages/flutter_localizations/lib/src/material_localizations.dart b/packages/flutter_localizations/lib/src/material_localizations.dart
index 56875a0..477940e 100644
--- a/packages/flutter_localizations/lib/src/material_localizations.dart
+++ b/packages/flutter_localizations/lib/src/material_localizations.dart
@@ -97,25 +97,15 @@
     required intl.DateFormat shortMonthDayFormat,
     required intl.NumberFormat decimalFormat,
     required intl.NumberFormat twoDigitZeroPaddedFormat,
-  }) : assert(localeName != null),
-       _localeName = localeName,
-       assert(fullYearFormat != null),
+  }) : _localeName = localeName,
        _fullYearFormat = fullYearFormat,
-       assert(compactDateFormat != null),
        _compactDateFormat = compactDateFormat,
-       assert(shortDateFormat != null),
        _shortDateFormat = shortDateFormat,
-       assert(mediumDateFormat != null),
        _mediumDateFormat = mediumDateFormat,
-       assert(longDateFormat != null),
        _longDateFormat = longDateFormat,
-       assert(yearMonthFormat != null),
        _yearMonthFormat = yearMonthFormat,
-       assert(shortMonthDayFormat != null),
        _shortMonthDayFormat = shortMonthDayFormat,
-       assert(decimalFormat != null),
        _decimalFormat = decimalFormat,
-       assert(twoDigitZeroPaddedFormat != null),
        _twoDigitZeroPaddedFormat = twoDigitZeroPaddedFormat;
 
   final String _localeName;
@@ -298,7 +288,6 @@
   String pageRowsInfoTitle(int firstRow, int lastRow, int rowCount, bool rowCountIsApproximate) {
     String? text = rowCountIsApproximate ? pageRowsInfoTitleApproximateRaw : null;
     text ??= pageRowsInfoTitleRaw;
-    assert(text != null, 'A $_localeName localization was not found for pageRowsInfoTitle or pageRowsInfoTitleApproximate');
     return text
       .replaceFirst(r'$firstRow', formatDecimal(firstRow))
       .replaceFirst(r'$lastRow', formatDecimal(lastRow))
@@ -446,7 +435,6 @@
   ///    the short time pattern used in the `en_US` locale.
   @override
   TimeOfDayFormat timeOfDayFormat({ bool alwaysUse24HourFormat = false }) {
-    assert(alwaysUse24HourFormat != null);
     if (alwaysUse24HourFormat) {
       return _get24HourVersionOf(timeOfDayFormatRaw);
     }