bug: enum Select crashes when selecting the empty value (via #5463)

* add failing tests

* fix property access

* @babel/plugin-proposal-optional-chaining

test/e2e-cypress/static/documents/bugs/5452/openapi.yaml

@@ -0,0 +1,20 @@
+openapi: "3.0.0"
+info:
+  title: Testcase API
+  version: 2.0.0
+paths:
+  '/endpoint':
+    get:
+      parameters:
+        - name: type
+          in: query
+          example: fruit
+          schema:
+            type: string
+            enum:
+              - fruit
+              - vegetable
+              - drink
+      responses:
+        '200':
+          description: 200 response

test/e2e-cypress/static/documents/bugs/5452/swagger.yaml

@@ -0,0 +1,19 @@
+swagger: "2.0"
+info:
+  title: Testcase API
+  version: 2.0.0
+paths:
+  '/endpoint':
+    get:
+      parameters:
+        - name: type
+          in: query
+          x-example: fruit
+          type: string
+          enum:
+            - fruit
+            - vegetable
+            - drink
+      responses:
+        '200':
+          description: 200 response