_has_integrated_gpu() needs to consider the desktop case

[jeremyszu]

In recovery (from a storage) case, the /var/lib/ubuntu-drivers-common/last_gfx_boot is empty. Thus, the _has_integrated_gpu() returns false in I+N laptop case. In this case, there is a iGPU actually.

---

During the recovery, a worker executes ubuntu-drivers install.

The expected result is "on-demand" but it goes to "on" because /var/lib/ubuntu-drivers-common/last_gfx_boot doesn't exist

`ubuntu-drivers install` calls `prime-select on-demand` calls enable_profile() and then enable_profile() calls _has_integrated_gpu() before switching mode.

Since _has_integrated_gpu() returns false, it won't switch nvidia mode

[jeremyszu (os369510)]

    def _has_integrated_gpu(self):
        status = False;

        path = '/var/lib/ubuntu-drivers-common/last_gfx_boot'
        if os.path.isfile(path):
            with open(path, 'r') as f:
                t = f.read()
                if t.find('8086') != -1 or t.lower().find('10de') != -1:
                    status = True
                f.close()

        return status
---
According to the discussion with Alberto[1], we are agree to check sysfs (e.g. vendor, chassis, etc..) instead.

https://chat.canonical.com/canonical/pl/buqmskei77bkucdqj9g7dwwxcy

[Alex Tu (alextu)]

the solution is included in the SRU from LP#1957094 and LP#1942789

[jeremyszu (os369510)]

as #2.