feat: run itests using ARM runners

[michaeldmitry]

Fixes #387

tandem PR: https://github.com/canonical/otel-ebpf-profiler-operator/pulls

[michaeldmitry]

This might break come itests if they don't pass a "arch": "arm64" constraint when deploying the charm. Should we make enabling this matrix conditional (e.g., behind a flag)?

[lucabello]

When we discussed this previously, we mentioned that we don't gain much coverage from running tests on multiple architectures, so we decided against it. If you want to rediscuss it, can you create a café topic for this?

[simskij]

When we discussed this previously, we mentioned that we don't gain much coverage from running tests on multiple architectures, so we decided against it. If you want to rediscuss it, can you create a café topic for this?

@lucabello We also said that for machine collectors, we will still need to do it for arm as well at the very least. That is also why we do it for grafana-agent and (I think?) otel-collector. In other words, this is still needed :)