refactor: use ci.yml as reusable workflow, remove redundant test workflows

Add workflow_call trigger to ci.yml so release-tests.yml can call it
directly. Remove test-unit.yml and test-build-package.yml since ci.yml
already covers both unit and build-package tests.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: EMaher

.github/workflows/ci.yml

@@ -4,6 +4,7 @@ on:
   pull_request:
     branches:
       - main
+  workflow_call:
 
 permissions:
   contents: read

.github/workflows/release-tests.yml

@@ -39,18 +39,13 @@ permissions:
   contents: read
 
 jobs:
-  unit-tests:
-    name: Unit Tests
-    uses: ./.github/workflows/test-unit.yml
-
-  build-package:
-    name: Build Package Integration Test
-    needs: unit-tests
-    uses: ./.github/workflows/test-build-package.yml
+  ci:
+    name: CI (Unit + Build Package Tests)
+    uses: ./.github/workflows/ci.yml
 
   all-types-integration:
     name: All-Types Integration Test
-    needs: build-package
+    needs: ci
     uses: ./.github/workflows/integration-test.yml
     with:
       sku: ${{ inputs.sku }}