Artifacts: use a different way of getting the UUID of a module (#55218)

(cherry picked from commit 59074fa)

Author: KristofferC

stdlib/Artifacts/src/Artifacts.jl

@@ -545,10 +545,10 @@ function jointail(dir, tail)
 end
 
 function _artifact_str(__module__, artifacts_toml, name, path_tail, artifact_dict, hash, platform, @nospecialize(lazyartifacts))
-    moduleroot = Base.moduleroot(__module__)
-    if haskey(Base.module_keys, moduleroot)
+    pkg = Base.PkgId(__module__)
+    if pkg.uuid !== nothing
         # Process overrides for this UUID, if we know what it is
-        process_overrides(artifact_dict, Base.module_keys[moduleroot].uuid)
+        process_overrides(artifact_dict, pkg.uuid)
     end
 
     # If the artifact exists, we're in the happy path and we can immediately