fix(ci): make the Vector IO CI follow the same pattern as others (#3164)

# What does this PR do?
Updates the integration-vector-io-tests workflow to run daily tests on
Python 3.13 while limiting regular PR tests to Python 3.12 only.

The PR also improves the concurrency configuration to prevent workflow
conflicts between main branch runs and PR runs.

## Test Plan


[![testinprod](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/WjlTemxb6oA4PgZFmj08/2645295d-f421-49ae-8f3f-f4672d8204e2/testinprod.jpeg)](https://app.graphite.dev/settings/meme-library?org=llamastack)

Author: ashwinb

.github/workflows/integration-vector-io-tests.yml

@@ -14,9 +14,11 @@ on:
       - 'pyproject.toml'
       - 'requirements.txt'
       - '.github/workflows/integration-vector-io-tests.yml' # This workflow
+  schedule:
+    - cron: '0 0 * * *'  # (test on python 3.13) Daily at 12 AM UTC
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
+  group: ${{ github.workflow }}-${{ github.ref == 'refs/heads/main' && github.run_id || github.ref }}
   cancel-in-progress: true
 
 jobs:
@@ -25,7 +27,7 @@ jobs:
     strategy:
       matrix:
         vector-io-provider: ["inline::faiss", "inline::sqlite-vec", "inline::milvus", "remote::chromadb", "remote::pgvector", "remote::weaviate", "remote::qdrant"]
-        python-version: ["3.12", "3.13"]
+        python-version: ${{ github.event.schedule == '0 0 * * *' && fromJSON('["3.12", "3.13"]') || fromJSON('["3.12"]') }}
       fail-fast: false # we want to run all tests regardless of failure
 
     steps: