chore(ci): correct the notify-datadog-release job (#17705)

## Description

Workflow automation API does not take in a JSON object with arbitrary keys as input body; rather, it takes in a single `input` string. We need to send our data as a JSON string to be parsed by the workflow downstream

## Testing

https://app.datadoghq.com/workflow/dd0d5405-b38c-4f4f-8f4c-c0cd4a65d4d6?debugItem=workflow-data&instance=7b93ae7c-7cfa-419b-b1b3-9b17aac0cbbb

https://gitlab.ddbuild.io/DataDog/apm-reliability/dd-trace-py/-/jobs/1635417293

Did a manual trigger from gitlab CI to verify e2e. Note that this was from a branch trigger, not a tag trigger where this usually needs to run

## Risks

<!-- Note any risks associated with this change, or "None" if no risks -->

## Additional Notes

I had claude do the `jq` stuff


Co-authored-by: gyuheon.oh <gyuheon.oh@datadoghq.com>

Author: gyuheon0h

.gitlab/release.yml

@@ -55,21 +55,20 @@ notify_datadog_release:
   before_script:
     - apt-get update && apt-get install --no-install-recommends -y curl jq
     - >-
-      DD_STS_API_KEY=$(curl -sS
-      -H "Authorization: Bearer ${DD_STS_OIDC_TOKEN}"
-      "https://dd-sts.us1.ddbuild.io/sts/datadog/exchange?policy=dd-trace-py-gitlab")
-    - >-
-      DD_STS_APP_KEY=$(curl -sS
+      DD_STS_RESPONSE=$(curl -sS
       -H "Authorization: Bearer ${DD_STS_OIDC_TOKEN}"
       "https://dd-sts.us1.ddbuild.io/sts/datadog/exchange?policy=dd-trace-py-gitlab-app-key")
-    - export DD_API_KEY=$(echo "$DD_STS_API_KEY" | jq -re '.api_key')
-    - export DD_APP_KEY=$(echo "$DD_STS_APP_KEY" | jq -re '.application_key')
+    - export DD_API_KEY=$(echo "$DD_STS_RESPONSE" | jq -re '.api_key')
+    - export DD_APP_KEY=$(echo "$DD_STS_RESPONSE" | jq -re '.application_key')
   script:
+    - sleep 3
     - |
       echo "Tag: ${CI_COMMIT_TAG} -> Commit SHA: ${CI_COMMIT_SHA}"
+      PAYLOAD="{\"version\": \"${CI_COMMIT_TAG}\", \"git_commit_sha\": \"${CI_COMMIT_SHA}\"}"
+      BODY=$(jq -n --arg input "$PAYLOAD" '{"meta": {"payload": {"input": $input}}}')
       curl --retry 3 --retry-delay 2 --fail -X POST \
         -H "Content-Type: application/json" \
         -H "DD-API-KEY: ${DD_API_KEY}" \
         -H "DD-APPLICATION-KEY: ${DD_APP_KEY}" \
-        -d "{\"meta\": {\"payload\": {\"version\": \"${CI_COMMIT_TAG}\", \"git_commit_sha\": \"${CI_COMMIT_SHA}\"}}}" \
+        -d "$BODY" \
         https://api.datadoghq.com/api/v2/workflows/dd0d5405-b38c-4f4f-8f4c-c0cd4a65d4d6/instances