document additional bootstrap issues

[ykethan]

Describe the content issue:
A clear and concise description of what the content issue is. Is there content missing or is there incorrect content?

document additional bootstrapping troubleshooting: #7482
Such as checking the CDKToolKit stack events for failures
Mitigation steps if the stack failed on asset bucket when recreating the toolkit stack.

URL page where content issue is:
https://docs.amplify.aws/react/build-a-backend/troubleshooting/stack-cdktoolkit-already-exists/