fix context canceled downgrade

[orouz]

Summary of your changes

fix for when we don't downgrade a context canceled error to a warning even though the error text includes that exact phrase

same error, different log levels:

because this:

rpc error: code = Canceled desc = context canceled // grpc#status.Error(codes.Canceled, "context canceled")

returned false in hasErrorType(context.Canceled,...)

it now returns true by checking the error message string

[mergify]

This pull request does not have a backport label. Could you fix it @orouz? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 8./d branch. /d is the digit
• backport-active-all is the label that automatically backports to all active branches.
• backport-active-8 is the label that automatically backports to all active minor branches for the 8 major.
• backport-active-9 is the label that automatically backports to all active minor branches for the 9 major.