docs: log a skipped unparseable folder entry instead of silently swallowing

get_folders' per-entry except swallowed a _folder_name failure with no log line, unlike
every sibling handler in the file - add a log.debug so a dropped folder is visible.

Signed-off-by: disqualifier <dev@disqualifier.me>

src/aiomail/client.py

@@ -176,7 +176,8 @@ class IMAPClient:
         for folder in folder_list or []:
             try:
                 name = _folder_name(folder)
-            except Exception:
+            except Exception as exc:
+                log.debug("skipping unparseable folder entry %r: %s", folder, exc)
                 continue
             if name is not None:
                 folders.append(name)