Infrastructure: add check for Azure credentials in build workflow (Mu…

…dlet#7548)

<!-- Keep the title short & concise so anyone non-technical can
understand it,
     the title appears in PTB changelogs -->
#### Brief overview of PR changes/additions
Add check for Azure credentials in build workflow
#### Motivation for adding to Mudlet
Fix builds from forks
#### Other info (issues closed, discussion etc)

---------

Co-authored-by: Vadim Peretokin <[email protected]>

.github/workflows/build-mudlet-win.yml

@@ -79,13 +79,13 @@ jobs:
 
     - name: (Windows) Login to Azure
       uses: azure/login@v2
-      if: github.repository == 'Mudlet/Mudlet'
+      if: ${{ github.event.pull_request.head.repo.full_name == 'Mudlet/Mudlet' }}
       with:
         creds: ${{ secrets.AZURE_CREDENTIALS }}
 
     - name: Get Azure access token for code signing
       shell: pwsh
-      if: github.repository == 'Mudlet/Mudlet'
+      if: ${{ github.event.pull_request.head.repo.full_name == 'Mudlet/Mudlet' }}
       run: |
         $token = (az account get-access-token --resource https://codesigning.azure.net | ConvertFrom-Json).accessToken
         "::add-mask::$token"