feat(cli): support prereleases (#6085)

We previously errored when a user had prerelease dependencies, this PR
passes the `--prereleases=allow` flag to our `uv pip install` call.

This PR also adds a test to verify that said deployments will build and
run as expected.

libs/cli/examples/graph_prerelease_reqs/langgraph.json

@@ -0,0 +1,11 @@
+{
+    "python_version": "3.12",
+    "dependencies": [
+      "."
+    ],
+    "graphs": {
+      "agent": "./agent.py:graph"
+    },
+    "env": "../.env"
+  }
+