Explicitly install imagemagick in CI

[jrhoads]

Purpose

Paperclip-related problems in CI pointed to imagemagick not being installed.

Turns out that the new image for ubuntu-latest used in CI is now based on ubuntu-24.04, where it previously was based on ubuntu-22.04. They have different default packages installed. as outlined in
https://github.com/actions/runner-images/blob/ubuntu22/20250105.1/images/ubuntu/Ubuntu2204-Readme.md#installed-apt-packages
and https://github.com/actions/runner-images/blob/ubuntu24/20250105.1/images/ubuntu/Ubuntu2404-Readme.md#installed-apt-packages

In 22.04 imagemagick was already installed, whereas in 24.04 it is not installed by default.

Approach

Explicitly installs imgagemagick in CI

Types of changes

• Bug fix (non-breaking change which fixes an issue)

• New feature (non-breaking change which adds functionality)

• Breaking change (fix or feature that would cause existing functionality to change)

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