Docker image is pinned when already pinned

[varunsh-coder]

See this example:
https://github.com/fleetdm/fleet/pull/10205/files/0d98d9f31120b05f57d757d6ac96bce5632bd6d9..5ce95d8bf8496f39eac930a9d90c2e8af27b3caf

We need to check if the image is already pinned, then, it should not be pinned again.

[varunsh-coder]

@Devils-Knight can you please take this up? Do add a test case for this scenario.

[Devils-Knight]

@varunsh-coder I think there is already code in place for this scenario, view here.
The file above mentioned has pinned the image twice so it just removed one of the hash.

[varunsh-coder]

This is released. Good work @Devils-Knight!