ci: Remove invalid step from GAR build workflow (#3164)

## What ❔

<!-- What are the changes this PR brings about? -->
<!-- Example: This PR adds a PR template to the repo. -->
<!-- (For bigger PRs adding more context is appreciated) -->

## Why ❔

There is no need to remove local docker image.
<!-- Why are these changes done? What goal do they contribute to? What
are the principles behind them? -->
<!-- Example: PR templates ensure PR reviewers, observers, and future
iterators are in context about the evolution of repos. -->

## Checklist

<!-- Check your PR fulfills the following items. -->
<!-- For draft PRs check the boxes as you complete them. -->

- [x] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [ ] Tests for the changes have been added / updated.
- [ ] Documentation comments have been added / updated.
- [ ] Code has been formatted via `zkstack dev fmt` and `zkstack dev
lint`.

.github/workflows/build-prover-fri-gpu-gar-and-circuit-prover-gpu-gar.yml

@@ -69,10 +69,6 @@ jobs:
             --tag europe-docker.pkg.dev/matterlabs-infra/matterlabs-docker/prover-fri-gpu-gar:2.0-${{ inputs.protocol_version }}-${{ inputs.image_tag_suffix }} \
             us-docker.pkg.dev/matterlabs-infra/matterlabs-docker/prover-fri-gpu-gar:2.0-${{ inputs.protocol_version }}-${{ inputs.image_tag_suffix }}
 
-      - name: Remove prover-gpu-fri-gar image to free space
-        run: |
-          docker image rm us-docker.pkg.dev/matterlabs-infra/matterlabs-docker/prover-fri-gpu-gar:2.0-${{ inputs.protocol_version }}-${{ inputs.image_tag_suffix }}
-
       - name: Move Setup data from prover-gpu-fri-gar to circuit-prover-gpu-gar
         run: |
           mv -v docker/prover-gpu-fri-gar/*.bin docker/circuit-prover-gpu-gar/