adjusting validation library format and adding test cases

Signed-off-by: aramissennyeydd <aramis.sennyey@doordash.com>

packages/backend-openapi-utils/package.json

@@ -35,7 +35,9 @@
   "dependencies": {
     "@apidevtools/swagger-parser": "^10.1.0",
     "@backstage/backend-plugin-api": "workspace:^",
+    "@backstage/backend-test-utils": "workspace:^",
     "@backstage/errors": "workspace:^",
+    "@backstage/types": "workspace:^",
     "@types/express": "^4.17.6",
     "@types/express-serve-static-core": "^4.17.5",
     "ajv": "^8.16.0",
@@ -45,6 +47,7 @@
     "json-schema-to-ts": "^3.0.0",
     "lodash": "^4.17.21",
     "mockttp": "^3.13.0",
+    "msw": "^1.0.0",
     "openapi-merge": "^1.3.2",
     "openapi3-ts": "^3.1.2"
   },