Add test for parenthesized patterns without comma separation

Co-authored-by: CyrusNajmabadi <4564579+CyrusNajmabadi@users.noreply.github.com>

Author: Copilot

src/Workspaces/CSharpTest/Formatting/FormattingTests_Patterns.cs

@@ -654,4 +654,46 @@ void M(object former, object latter)
                 }
             }
             """);
+
+    [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/54434")]
+    public Task FormatPropertyPatternInParenthesizedPattern1()
+        => AssertFormatAsync("""
+            class C
+            {
+                void M(object value)
+                {
+                    if (
+                        value is not (
+                        {
+                            Expression: IdentifierNameSyntax
+                            {
+                                Identifier: { ValueText: var identifier }
+                            }
+                        }
+                        )
+                    )
+                    {
+                    }
+                }
+            }
+            """, """
+            class C
+            {
+                void M(object value)
+                {
+                    if (
+                        value is not (
+                    {
+                        Expression: IdentifierNameSyntax
+                        {
+                            Identifier: { ValueText: var identifier }
+                        }
+                    }
+                        )
+                    )
+                    {
+                    }
+                }
+            }
+            """);
 }