Hotfix: call shared.state.end() after postprocessing done

[aria1th]

Description

The shared.state.end() was missing in modules/postprocessing.py.

This will result the invalid API response as result after the job is done:

{'progress': 0.01,
 'eta_relative': 8755.73311328888,
 'state': {'skipped': False,
  'interrupted': False,
  'job': 'CodeFormer',
  'job_count': -1,
  'job_timestamp': '20231115141010',
  'job_no': 0,
  'sampling_step': 0,
  'sampling_steps': 20},
 'current_image': None,
 'textinfo': None}

The related test should be added to check API status.

Screenshots/videos:

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests