Remove an unreferences assist kind

Change-Id: I4accda710fececceff2fae3ba5a8014a89e504d4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/402760
Reviewed-by: Samuel Rawlins <[email protected]>
Auto-Submit: Brian Wilkerson <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: bwilkerson

pkg/analysis_server/lib/src/services/correction/assist.dart

@@ -482,11 +482,6 @@ abstract final class DartAssistKind {
     DartAssistKindPriority.SURROUND_WITH_WHILE,
     "Surround with 'while'",
   );
-  static const UNWRAP_IF_BODY = AssistKind(
-    'dart.assist.unwrap.if',
-    DartAssistKindPriority.DEFAULT,
-    "Unwrap 'if' body",
-  );
   static const USE_CURLY_BRACES = AssistKind(
     'dart.assist.surround.curlyBraces',
     DartAssistKindPriority.DEFAULT,