fix: gracefully handle empty request bodies (via #4859)

test/e2e-cypress/static/documents/bugs/4838.yaml

@@ -0,0 +1,12 @@
+openapi: "3.0.0"
+
+paths:
+  /some/route:
+    post:
+      description: This should be visible
+      tags:
+        - Some
+      requestBody: {}
+      responses:
+        '200':
+          description: Description

test/e2e-cypress/tests/bugs/4838.js

@@ -0,0 +1,11 @@
+import repeat from "lodash/repeat"
+
+describe("#4838: empty request bodies result in endless loading", () => {
+  it("should render model content changes correctly", () => {
+    cy
+      .visit("/?url=/documents/bugs/4838.yaml")
+      .get("#operations-Some-post_some_route")
+      .click()
+      .contains("This should be visible")
+  })
+})