Fix how C_Cpp.default recursive include settings are defined (#13549)

Author: Colengms

Extension/package.json

@@ -900,31 +900,31 @@
                     "C_Cpp.default.recursiveIncludes.reduce": {
                         "type": "string",
                         "enum": [
+                            "",
                             "always",
                             "never",
                             "default"
                         ],
-                        "default": "default",
                         "markdownDescription": "%c_cpp.configuration.default.recursiveIncludes.reduce.markdownDescription%",
                         "scope": "resource"
                     },
                     "C_Cpp.default.recursiveIncludes.priority": {
                         "type": "string",
                         "enum": [
+                            "",
                             "beforeSystemIncludes",
                             "afterSystemIncludes"
                         ],
-                        "default": "afterSystemIncludes",
                         "markdownDescription": "%c_cpp.configuration.default.recursiveIncludes.priority.markdownDescription%",
                         "scope": "resource"
                     },
                     "C_Cpp.default.recursiveIncludes.order": {
                         "type": "string",
                         "enum": [
+                            "",
                             "depthFirst",
                             "breadthFirst"
                         ],
-                        "default": "depthFirst",
                         "markdownDescription": "%c_cpp.configuration.default.recursiveIncludes.order.markdownDescription%",
                         "scope": "resource"
                     },