Support migration of CcCompilationContext.directModuleMaps to NestedSet.

Previously a regression was fixed by exposing additional NestedSet field. Now taking it a step further, exposing just the NestedSet.

PiperOrigin-RevId: 820665506
Change-Id: I4898479bd03e7ebc0533957219f149a1e4e928cc
diff --git a/cc/common/cc_helper.bzl b/cc/common/cc_helper.bzl
index 529231b..5771773 100644
--- a/cc/common/cc_helper.bzl
+++ b/cc/common/cc_helper.bzl
@@ -167,7 +167,10 @@
     if hasattr(compilation_context, "additional_inputs"):
         transitive.append(compilation_context.additional_inputs())
     else:
-        transitive.append(depset(compilation_context._direct_module_maps))
+        direct_module_maps = compilation_context._direct_module_maps
+        if type(direct_module_maps) != "depset":
+            direct_module_maps = depset(direct_module_maps)
+        transitive.append(direct_module_maps)
         transitive.append(compilation_context._non_code_inputs)
         if compilation_context._module_map:
             transitive.append(depset([compilation_context._module_map.file()]))