Python: Don't import module as module_attr

For `from <pkg> import <attr>` we would use to treat the `<pkg>`
(ImportExpr) as a definition of the name `<attr>`.

Since this removes bad import-flow, and nothing broke, I'm guessing this
was never intentional.

python/ql/lib/semmle/python/dataflow/new/internal/ImportResolution.qll

@@ -95,7 +95,7 @@ module ImportResolution {
     )
     or
     exists(Alias a |
-      defn.asExpr() = [a.getValue(), a.getValue().(ImportMember).getModule()] and
+      defn.asExpr() = a.getValue() and
       a.getAsname().(Name).getId() = name and
       defn.getScope() = m
     )