chore(crypto): Removed unnecessary linter ignore

Author: tyllark

pkgs/crypto/lib/src/sha512.dart

@@ -6,7 +6,6 @@ import 'dart:convert';
 
 import 'digest.dart';
 import 'hash.dart';
-// ignore: uri_does_not_exist
 import 'sha512_fastsinks.dart'
     if (dart.library.js_interop) 'sha512_slowsinks.dart';
 import 'utils.dart';