fix(optimizer): don't externalize transitive dep package name with asset extension

[hi-ogawa]

Description

• closes The object is created with the old class name, but the instanceof check is performed with the renamed class name #18036

#16242 handled the case of require call, but it looks like it should cover import as well. This was suggested in #16242 (comment) and probably this is indeed necessary to handle external package name like import "some-package.pdf".

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