Gemini prompt caching

[enyst]

End-user friendly description of the problem this fixes or functionality that this introduces

• Include this change in the Release Notes. If checked, you must provide an end-user friendly description for your change below

---

Give a summary of what the PR does, explaining any non-trivial design decisions

---

Link of any specific issues this addresses

---

To run this PR locally, use the following command:

docker run -it --rm   -p 3000:3000   -v /var/run/docker.sock:/var/run/docker.sock   --add-host host.docker.internal:host-gateway   -e SANDBOX_RUNTIME_CONTAINER_IMAGE=docker.all-hands.dev/all-hands-ai/runtime:b24dfd3-nikolaik   --name openhands-app-b24dfd3   docker.all-hands.dev/all-hands-ai/openhands:b24dfd3

[mamoodi]

Just another small nudge for @enyst to check if this PR is still happening.

[enyst]

Certainly! Thanks for the nudge. Just for the record, there are at least three different issues with this in liteLLM. Currently prompt caching is not enabled in oh for Gemini, so things shouldn't break for people but I'll come back to this in a bit!

[mamoodi]

Were the litellm issues resolved at all?