Report only top-most deprecated module import

Fixes issue 13582

https://issues.dlang.org/show_bug.cgi?id=13582
In 2), there are two detailed cases.
2a) B is not a sub-module of `package.d`
2b) B is a sub-module of `package.d`

In case 2a), the two deprecation message is legitimate. the author  of `package.d` should address the issue.

In case 2b), I think compiler should accept the import of deprecated sub-module silently. because deprecating sub-module could be regarded like a deprecation of a module level symbol in non-deprecated module.