Fix GCC build error with std::to_char<double> (facebookincubator#11369)

Summary:
facebookincubator#11103 breaks GCC build
```
In instantiation of function template specialization 'facebook::velox::functions::(anonymous namespace)::padContent<double>' call to 'to_chars' is ambiguous
```

To minimize code changes, this PR add unsigned cast for ceil to fix it.

Pull Request resolved: facebookincubator#11369

Reviewed By: Yuhta

Differential Revision: D65420211

Pulled By: mbasmanova

fbshipit-source-id: 18aba3a62012a86d1bc3e7fec57dda54c992050e

velox/functions/lib/DateTimeFormatter.cpp

@@ -1532,10 +1532,10 @@ int32_t DateTimeFormatter::format(
         }
         case DateTimeFormatSpecifier::WEEK_OF_MONTH: {
           result += padContent(
-              ceil(
+              unsigned(ceil(
                   (7 + static_cast<unsigned>(calDate.day()) -
                    weekday.c_encoding() - 1) /
-                  7.0),
+                  7.0)),
               '0',
               token.pattern.minRepresentDigits,
               maxResultEnd,