Use Module interface in addRequiredDeps

Previously, addRequiredDeps directly called RequiredModuleNames directly on
ModuleBase. As a result, it failed to correctly track the dependencies
for the modules which are overriding RequiredModuleNames. cc_* were
those.

Fixing this by calling RequiredModuleNames via the Module interface.

Bug: 321626681
Test: go test ./... under filesystem
Change-Id: I79de616606b88277da0b3e86b21316ee83e0ec71