chore(falco.yaml): use HOME env var for ebpf probe path.

[FedeDP]

What type of PR is this?

/kind cleanup

Any specific area of the project related to this PR?

What this PR does / why we need it:

Since #2918 is now merged, we can freely use env var.
This is more correct since eg: falcoctl will copy built drivers there: https://github.com/falcosecurity/falcoctl/blob/main/pkg/driver/type/bpf.go#L55.
Most of the time, both falcoctl and Falco will run as root, thus the env var will resolve to the current /root/.falco/falco-bpf.o.
But if user decides to eg: have a Falco user with reduced privileges, she/he will still be able to let falcoctl install its ebpf probe and then Falco would start without issues.

Example output without and with sudo:

Wed Dec 13 17:10:40 2023: Opening 'syscall' source with BPF probe. BPF probe path: /home/federico/.falco/falco-bpf.o
Wed Dec 13 17:10:52 2023: Opening 'syscall' source with BPF probe. BPF probe path: /root/.falco/falco-bpf.o

Also, this was already the default behavior when FALCO_BPF_PROBE="" env var was passed:

falco/userspace/falco/app/actions/helpers_inspector.cpp

Line 114 in cbbcb61

const char *home = std::getenv("HOME");

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

[FedeDP]

/milestone 0.37.0

[incertum]

/approve

[FedeDP]

Wow Melissa, quicker than me 😆

[Andreagit97]

/approve

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Andreagit97, FedeDP, incertum

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [Andreagit97,FedeDP,incertum]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment