Use systemctl instead of services to install blackfire

[lolautruche]

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name: 🐞 Bug Fix
about: You found a bug
labels: bug

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Description

This PR changes sudo service blackfire-agent start to sudo systemctl start blackfire-agent

In case this PR edits any scripts:

• I have checked the edited scripts for syntax.
• I have tested the changes in an integration test (If yes, provide workflow YAML and link).