ci: Update nightly build workflow to delete existing main tags before generating new ones (#5694)

.github/workflows/nightly_build.yml

@@ -41,19 +41,16 @@ jobs:
           echo "main_tag=$MAIN_TAG" >> $GITHUB_OUTPUT
           echo "main_tag=$MAIN_TAG"
 
-      - name: Check if main tag already exists
+      - name: Delete existing tag if it exists
         id: check_main_tag
         run: |
           git fetch --tags
-          if git rev-parse -q --verify "refs/tags/${{ steps.generate_main_tag.outputs.main_tag }}" >/dev/null; then
-            echo "main_tag_exists=true" >> $GITHUB_OUTPUT
-          else
-            echo "main_tag_exists=false" >> $GITHUB_OUTPUT
-          fi
+          git tag -d ${{ steps.generate_main_tag.outputs.main_tag }} || true
+          git push --delete origin ${{ steps.generate_main_tag.outputs.main_tag }} || true
+          echo "main_tag_exists=false" >> $GITHUB_OUTPUT
 
       - name: Generate base nightly tag
         id: generate_base_tag
-        if: ${{ steps.check_main_tag.outputs.main_tag_exists == 'false' }}
         run: |
           # NOTE: This outputs the tag with the `v` prefix.
           BASE_TAG="$(uv run ./scripts/ci/pypi_nightly_tag.py base)"
@@ -62,7 +59,6 @@ jobs:
 
       - name: Commit tag
         id: commit_tag
-        if: ${{ steps.check_main_tag.outputs.main_tag_exists == 'false' }}
         run: |
           # If the main tag does not exist in GH, we create the base tag from the existing codebase.
 
@@ -95,13 +91,11 @@ jobs:
 
       - name: Checkout main nightly tag
         uses: actions/checkout@v4
-        if: ${{ steps.check_main_tag.outputs.main_tag_exists == 'true' }}
         with:
           ref: ${{ steps.generate_main_tag.outputs.main_tag }}
 
       - name: Retrieve Base Tag
         id: retrieve_base_tag
-        if: ${{ steps.check_main_tag.outputs.main_tag_exists == 'true' }}
         working-directory: src/backend/base
         run: |
           # If the main tag already exists, we need to retrieve the base version from the main tag codebase.