[Completion]Remove duplicate addition of default keyword

Change-Id: Ief8584a90c69c4b049b0eb28224d745576e1a374
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/434980
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Keerti Parthasarathy <[email protected]>

Author: keertip

pkg/analysis_server/lib/src/services/completion/dart/in_scope_completion_pass.dart

@@ -2885,9 +2885,6 @@ class InScopeCompletionPass extends SimpleAstVisitor<void> {
       keywordHelper.addKeyword(Keyword.CASE);
       keywordHelper.addKeywordAndText(Keyword.DEFAULT, ':');
       if (members.isNotEmpty) {
-        if (!members.any((element) => element is SwitchDefault)) {
-          keywordHelper.addKeywordAndText(Keyword.DEFAULT, ':');
-        }
         var element = members.elementBefore(offset);
         if (element != null) {
           _forStatement(element);