ASHWANI PANDEY Thank you for sharing the solution. It will greatly help others facing similar issues and looking for a solution. Microsoft Q&A has policy: Accept an answer that question authors cannot accept their own answers and hence I am posting your answer in case you like to accept.
The issue was using
GITHUB_TOKEN to deploy container App in
registryPassword which didn't have right permissions and hence it was denied. You had created a new token with read permissions and the issue was resolved.