Simplify GitHub Action (#77)

# Simplify GitHub Action

## ♻️ Current situation & Problem
- A release tag doesn't work for the environment selection

## ⚙️ Release Notes 
- Simplifies the GitHub Action

### Code of Conduct & Contributing Guidelines 

By submitting creating this pull request, you agree to follow our [Code
of
Conduct](https://github.com/StanfordBDHG/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/StanfordBDHG/.github/blob/main/CONTRIBUTING.md):
- [x] I agree to follow the [Code of
Conduct](https://github.com/StanfordBDHG/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/StanfordBDHG/.github/blob/main/CONTRIBUTING.md).

.github/workflows/beta-deployment.yml

@@ -49,12 +49,10 @@ jobs:
       - name: Determine Environment
         id: set-env
         run: |
-          if [[ "${{ github.event_name }}" == "workflow_dispatch" ]]; then
-            echo "environment=${{ inputs.environment }}" >> $GITHUB_OUTPUT
-          elif [[ "${{ github.event_name }}" == "workflow_call" ]]; then
-            echo "environment=${{ inputs.environment }}" >> $GITHUB_OUTPUT
-          else
+          if [[ -z "${{ inputs.environment }}" ]]; then
             echo "environment=staging" >> $GITHUB_OUTPUT
+          else
+            echo "environment=${{ inputs.environment }}" >> $GITHUB_OUTPUT
           fi
   vars:
     name: Inject Environment Variables In Deployment Workflow