chore(<test>): Separate infrastructure commands from actual test commands in CI and scripts

[hbelmiro]

Chore description

Currently, several scripts mix infrastructure code, such as creating virtual environments or installing tools with apt-get, with actual test invocations.
presubmit-backend-visualization.sh is an example.

We need to separate infrastructure from actual test invocation code, to make it easier for contributors to run tests locally without unnoticed/unwanted changes in the contributor's machine.

This issue will likely turn into an epic after preliminary investigation.

Labels

/area testing

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[hbelmiro]

/assign