fix: add manager command for group image resize task

[progmatic-99]

Fixes frontend#7761

Short description of what this resolves:

Changes proposed in this pull request:

Checklist

• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream development branch.
• The unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

• All the functions created/modified in this PR contain relevant docstrings.

[lgtm-com]

This pull request introduces 1 alert when merging 9ddc514 into 7ca377d - view on LGTM.com

new alerts:

• 1 for Testing equality to None

[codecov]

Codecov Report

Merging #8421 (9ddc514) into development (7ca377d) will decrease coverage by 0.03%.
The diff coverage is 0.00%.

@@               Coverage Diff               @@
##           development    #8421      +/-   ##
===============================================
- Coverage        65.63%   65.60%   -0.04%     
===============================================
  Files              306      306              
  Lines            15935    15943       +8     
===============================================
  Hits             10459    10459              
- Misses            5476     5484       +8     

Impacted Files	Coverage Δ
manage.py	0.00% <0.00%> (ø)

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[codedsun]

Nice work