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]

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