fix: lambda layer release workflow cannot find layer.zip (#350)

### What does this pull request do?
Fixes the lambda layer release workflow. Currently it cannot find
`layer.zip` file.
```
gh release create --target "$GITHUB_REF_NAME" \
     --title "Release lambda-v0.9.0-2568924" \
     --notes-file release_notes.md  \
     --draft \
     "lambda-v0.9.0-2568924" \
     layer_arns.tf layer.zip
  echo Removing release_notes.md ...
  rm -f release_notes.md
  shell: /usr/bin/bash -e {0}
  env:
    COMMERCIAL_REGIONS: us-east-1, us-east-2, us-west-1, us-west-2, ap-south-1, ap-northeast-[3](https://github.com/aws-observability/aws-otel-python-instrumentation/actions/runs/14318246265/job/40130001673#step:11:3), ap-northeast-2, ap-southeast-1, ap-southeast-2, ap-northeast-1, ca-central-1, eu-central-1, eu-west-1, eu-west-2, eu-west-3, eu-north-1, sa-east-1
    LAYER_NAME: AWSOpenTelemetryDistroPython
    TERRAFORM_CLI_PATH: /home/runner/work/_temp/a8[4](https://github.com/aws-observability/aws-otel-python-instrumentation/actions/runs/14318246265/job/40130001673#step:11:4)a8d1f-ec49-4a11-9b46-88a32b10322f
    GITHUB_TOKEN: ***
no matches found for `layer.zip`
```

This is because when the zip file is downloaded
[here](https://github.com/aws-observability/aws-otel-python-instrumentation/blob/main/.github/workflows/release-lambda.yml#L92),
the artifact is actually named `aws-opentelemetry-python-layer.zip` due
to
[here](https://github.com/aws-observability/aws-otel-python-instrumentation/blob/main/.github/workflows/release-lambda.yml#L53C8-L55C74).

By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice.

Author: yiyuan-he

.github/workflows/release-lambda.yml

@@ -186,6 +186,9 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: layer.zip
+      - name: Rename layer file
+        run: |
+          cp aws-opentelemetry-python-layer.zip layer.zip
       - name: Get commit hash
         id: commit
         run: echo "sha_short=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT