Housekeeping: Use npm ci when setting up the environment

[Fuzzy3]

Which issue does this PR close?

This PR closes no issue

What is the new behavior?

This bug: npm/cli#4828 forced us to move away from using the npm ci command when setting up the environment. However the bug was fixed and released in npm/cli v11.3.0 and thus we can now change the step back to using the npm ci command again.

Does this PR introduce a breaking change?

• Yes
• No

Are there any additional context?

Checklist:

The following tasks should be carried out in sequence in order to follow the process of contributing correctly.

Reminders

• Make sure you have implemented tests following the guidelines in: "The good: Test".
• Make sure you have updated the cookbook with examples and showcases (for bug fixes, enhancements & new components).

Review

• Determine if your changes are a fix, feature or breaking-change, and add the matching label to your PR. If it is tooling, dependency updates or similar, add ignore-for-release.
• Do a self-review.
• Request that the changes are code-reviewed
• Request that the changes are UX reviewed (only necessary if your PR introduces visual changes)

When the pull request has been approved it will be merged to develop by Team Kirby.

[RasmusKjeldgaard]

YES! 👏