cc_shared_library: fix aspect traversal over new attrs.

In our custom cc_* rules, we're using attrs other than deps to indicate CcInfo deps, like static/shared for the cc proxy rule, and dynamic_deps in cc_shared_library itself.

This fixes shared library linking when it comes to linking our custom cc_library_static combined targets, for example.

Bug: 183064430

Test: TH
Change-Id: I600f951b80386f835b4779f87648a0fd2c97aa60