esque describe consumergroup doesn't show topic for offset summary

[swenzel]

This is only for non-verbose mode.

Expected output:

>>> esque describe consumergroup mygroup                      
group_id:          mygroup
group_coordinator: mybroker
offsets:
  mytopic (min, max over 50 partitions):
    consumer_offset:      9080383, 9569775
    topic_low_watermark:  2710, 4067
    topic_high_watermark: 9096612, 9586679
    consumer_lag:         15606, 16904
meta:
  group_id:      mygroup
  protocol:      ''
  state:         Empty
  error_code:    0
  protocol_type: consumer
  members:
    []

actual output

>>> esque describe consumergroup mygroup                      
group_id:          mygroup
group_coordinator: mybroker
offsets:
  consumer_offset:      9080383, 9569775
  topic_low_watermark:  2710, 4067
  topic_high_watermark: 9096612, 9586679
  consumer_lag:         15606, 16904
meta:
  group_id:      mygroup
  protocol:      ''
  state:         Empty
  error_code:    0
  protocol_type: consumer
  members:
    []