Changing the command to clean up docker images

[agunapal]

Description

It seems like we were not cleaning up the older images in the regression run correctly.

Fixes #(issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Feature/Issue validation/testing

Docker regression Run

Checklist:

• Did you have fun?
• Have you added tests that prove your fix is effective or that this feature works?
• Has code been commented, particularly in hard-to-understand areas?
• Have you made corresponding changes to the documentation?

[codecov]

Codecov Report

Merging #2726 (1d6cf58) into master (551d2c7) will not change coverage.
The diff coverage is n/a.

❗ Current head 1d6cf58 differs from pull request most recent head 0096d57. Consider uploading reports for the commit 0096d57 to get more accurate results

@@           Coverage Diff           @@
##           master    #2726   +/-   ##
=======================================
  Coverage   72.44%   72.44%           
=======================================
  Files          85       85           
  Lines        3963     3963           
  Branches       58       58           
=======================================
  Hits         2871     2871           
  Misses       1088     1088           
  Partials        4        4           

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[mreso]

LGTM
edit: too late....