The 'refusing to allow an OAuth App to create or update workflow' error is not handled

[flagmanAndrew]

Steps to reproduce:

1. Make sure that you have invalid login information for github stored in Windows Credentials Manager
2. Create a pull request for a branch (on upstream) created after April 2021

Actual result: dxCherry shows that it attempted to make a pull request and then nothing. In fact, the following error appeared (in log for dxCherry): ! [remote rejected] master -> master (refusing to allow an OAuth App to create or update workflow .github/workflows/file.yml without workflow scope)

Expected result: dxSherry shows that this error appeared

Solution is described at: gitextensions/gitextensions#4916 (comment)