test(imap-move): satisfy require_trailing_commas in COPYUID-less test

`dart analyze --fatal-infos` (used by CI but not by my local
`flutter analyze` invocation) flagged the inline `searchResults`
literal as missing a trailing comma. Move the literal to a
`const` map with a trailing comma so the lint passes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

test/unit/email_repository_impl_test.dart

@@ -1181,8 +1181,8 @@ void main() {
         const criteria = 'HEADER Message-ID "$messageId"';
         final spy = SnoozeSpyImapClient(
           // No copyUidValidity → no COPYUID in the MOVE response.
-          searchResults: {
-            criteria: const [99]
+          searchResults: const {
+            criteria: [99],
           },
         );
         final r = _makeRepos(imapConnect: (_, __, ___) async => spy);