fix: provide JSON editor for x-www-form-urlencoded bodies lacking properties (via #5180)

test/e2e-cypress/tests/bugs/5072.js

@@ -0,0 +1,22 @@
+describe("#5072: x-www-form-urlencoded request body input when `properties` is missing", () => {
+  it("should provide a JSON input for an empty object schema", () => {
+    cy
+      .visit("?url=/documents/bugs/5072/empty.yaml")
+      .get("#operations-default-postObject")
+      .click()
+      .get(".try-out__btn")
+      .click()
+      .get(`.opblock-section-request-body textarea`)
+      .should("have.value", "{}")
+  })
+  it("should provide a JSON input for an additionalProperties object schema", () => {
+    cy
+      .visit("?url=/documents/bugs/5072/additional.yaml")
+      .get("#operations-default-postObject")
+      .click()
+      .get(".try-out__btn")
+      .click()
+      .get(`.opblock-section-request-body textarea`)
+      .contains(`"additionalProp1": "string"`)
+  })
+})