Optimize attribute existence check by inverting condition

Co-authored-by: ToddGrun <6785178+ToddGrun@users.noreply.github.com>

Author: Copilot

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/BlazorDataAttributeCompletionItemProvider.cs

@@ -82,30 +82,33 @@ public ImmutableArray<RazorCompletionItem> GetCompletionItems(RazorCompletionCon
                 continue;
             }
 
-            // Check if the attribute already exists on the element
-            var alreadyExists = false;
-            foreach (var attribute in attributes)
+            // If not currently editing this attribute, check if it already exists
+            if (selectedAttributeName != attributeName)
             {
-                var existingAttributeName = attribute switch
+                var alreadyExists = false;
+                foreach (var attribute in attributes)
                 {
-                    MarkupAttributeBlockSyntax attributeBlock => attributeBlock.Name.GetContent(),
-                    MarkupMinimizedAttributeBlockSyntax minimizedAttributeBlock => minimizedAttributeBlock.Name.GetContent(),
-                    _ => null
-                };
+                    var existingAttributeName = attribute switch
+                    {
+                        MarkupAttributeBlockSyntax attributeBlock => attributeBlock.Name.GetContent(),
+                        MarkupMinimizedAttributeBlockSyntax minimizedAttributeBlock => minimizedAttributeBlock.Name.GetContent(),
+                        _ => null
+                    };
+
+                    if (existingAttributeName == attributeName)
+                    {
+                        alreadyExists = true;
+                        break;
+                    }
+                }
 
-                if (existingAttributeName == attributeName)
+                if (alreadyExists)
                 {
-                    alreadyExists = true;
-                    break;
+                    // Attribute already exists and is not the one currently being edited
+                    continue;
                 }
             }
 
-            if (alreadyExists && selectedAttributeName != attributeName)
-            {
-                // Attribute already exists and is not the one currently being edited
-                continue;
-            }
-
             var insertText = attributeName;
             var isSnippet = false;