- Replace the "recurse one layer deep" approach of `LLFirDependentModuleProviders` with a flattened list of dependency symbol providers. - This refactoring is a necessary component of supporting combined symbol providers.
- Replace the "recurse one layer deep" approach of `LLFirDependentModuleProviders` with a flattened list of dependency symbol providers. - This refactoring is a necessary component of supporting combined symbol providers.