chore(deps): bump flask from 3.0.3 to 3.1.3 in /iap (#13881)

Bumps [flask](https://github.com/pallets/flask) from 3.0.3 to 3.1.3.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/main/CHANGES.rst)
- [Commits](pallets/flask@3.0.3...3.1.3)

---
updated-dependencies:
- dependency-name: flask
  dependency-version: 3.1.3
  dependency-type: direct:production
...

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Author: dependabot[bot]

iap/app_engine_app/requirements.txt

@@ -1,2 +1,2 @@
-Flask==3.0.3
+Flask==3.1.3
 Werkzeug==3.1.4

iap/requirements.txt

@@ -1,5 +1,5 @@
 cryptography==45.0.1
-Flask==3.0.3
+Flask==3.1.3
 google-auth==2.38.0
 gunicorn==23.0.0
 requests==2.32.4