Fix double encoding

This note["tags"] has already been encoded utf-8 in Simplenote#get_note.

```
Error detected while processing function simplenote#SimpleNote:
line   37:
Traceback (most recent call last):
  File "<string>", line 10, in <module>
  File "<string>", line 499, in list_note_index_in_scratch_buffer
  File "<string>", line 346, in format_title
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 4: ordinal not in range(128)
```