Configure virtual screen resolution on Arm64 Photon OS on ESXi on Arm

In /boot/grub/grub.cfg modify the line beginning with set gfxmode=, and set a value set gfxmode="1152x864".

See https://blogs.vmware.com/arm/2021/03/23/setting-virtual-screen-resolution-for-esxi-arm-vms/, actually there is no VMware virtual SVGA adapter for ESXi Arm Windows VMs.