[Files]: Fix format for errors reported when calling getMetada.

String subtitution does not work correctly when tests are run. As a
result we get
"getMetadata error for: %s; error: (%d, %s, %s) ..." in the logs, rather
than correctly formatted strings. Also, if the error is not
DOMException, relying on presence or name, code, and message is a
mistake. It is better to use toString() method and let the exception
format itself. This is a follow-up to crrev.com/c/3812720

Bug: 1348455
Change-Id: I57325bdbc54f3f65ce92419b1ba4074fd6b7929a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3815102
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Bo Majewski <majewski@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1032410}

ui/file_manager/file_manager/foreground/js/metadata/file_system_metadata_provider.js

@@ -37,9 +37,8 @@ export class FileSystemMetadataProvider extends MetadataProvider {
                 // console.error causes them to fail because of JSErrorCount.
                 // This error is an acceptable condition.
                 console.warn(
-                    'getMetadata error for: %s; error: (%d, %s, %s)',
-                    request.entry.toURL(), error.code, error.name,
-                    error.message);
+                    `getMetadata error for '${request.entry.toURL()}':`,
+                    error.toString());
                 return new MetadataItem();
               });
     }));