fix: different output of cli bundle and redoc

fixes #547

Author: RomanHotsiy

src/components/__tests__/__snapshots__/DiscriminatorDropdown.test.tsx.snap

@@ -80,16 +80,12 @@ exports[`Components SchemaView discriminator should correctly render discriminat
             "options": "<<<filtered>>>",
             "pattern": undefined,
             "rawSchema": Object {
-              "allOf": undefined,
               "default": undefined,
-              "parentRefs": Array [],
               "type": "string",
             },
             "readOnly": false,
             "schema": Object {
-              "allOf": undefined,
               "default": undefined,
-              "parentRefs": Array [],
               "type": "string",
             },
             "title": "",

src/services/OpenAPIParser.ts

@@ -192,6 +192,14 @@ export class OpenAPIParser {
       parentRefs: [],
     };
 
+    // avoid mutating inner objects
+    if (receiver.properties !== undefined && typeof receiver.properties === 'object') {
+      receiver.properties = { ...receiver.properties };
+    }
+    if (receiver.items !== undefined && typeof receiver.items === 'object') {
+      receiver.items = { ...receiver.items };
+    }
+
     const allOfSchemas = schema.allOf.map(subSchema => {
       const resolved = this.deref(subSchema, forceCircular);
       const subRef = subSchema.$ref || undefined;