ci: fix tags processing in core reusable template (#3310)

## What ❔
Fix docker tag in core reusable template

## Why ❔
EN alpha part was missed in tag

## Checklist

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- [x] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [x] Tests for the changes have been added / updated.
- [x] Documentation comments have been added / updated.
- [x] Code has been formatted via `zkstack dev fmt` and `zkstack dev
lint`.

.github/workflows/new-build-core-template.yml

@@ -197,10 +197,8 @@ jobs:
         shell: bash
         run: |
           echo PLATFORM=$(echo ${{ matrix.platforms }} | tr '/' '-') >> $GITHUB_ENV
-          echo IMAGE_TAG_SHA=$(git rev-parse --short HEAD) >> $GITHUB_ENV
-          # Support for custom tag suffix
           if [ -n "${{ inputs.image_tag_suffix }}" ]; then
-            echo IMAGE_TAG_SHA_TS="${{ inputs.image_tag_suffix }}" >> $GITHUB_ENV
+            echo IMAGE_TAG_SHA_TS="${{ env.IMAGE_TAG_SUFFIX }}" >> $GITHUB_ENV
           else
             echo IMAGE_TAG_SHA_TS=$(git rev-parse --short HEAD)-$(date +%s) >> $GITHUB_ENV
           fi