Fix main build: remove dangling Tool.Execution reference in BuildLegacyWireProtocolTool (#1660)

Author: halter73

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs

@@ -262,7 +262,6 @@ internal Tool BuildLegacyWireProtocolTool()
             InputSchema = ProtocolTool.InputSchema,
             OutputSchema = legacyOutputSchema,
             Annotations = ProtocolTool.Annotations,
-            Execution = ProtocolTool.Execution,
             Icons = ProtocolTool.Icons,
             Meta = ProtocolTool.Meta,
         };