Problem: Building on arm64 Linux via Meta/ladybird.py fails during vcpkg
bootstrap with “CMake was unable to find a build program corresponding
to Ninja” unless VCPKG_FORCE_SYSTEM_BINARIES=1 is set by hand.
Cause: vcpkg ships no prebuilt tool binaries for arm64 Linux — so it has
to be told to use the system CMake and Ninja. CI and the devcontainer
already set the variable for arm64, but ladybird.py only auto-set it for
riscv64 — leaving the documented build path broken on arm64 Linux.
Fix: Also set VCPKG_FORCE_SYSTEM_BINARIES on AArch64 Linux hosts —
matching the condition CI already uses.
Fixes https://github.com/LadybirdBrowser/ladybird/issues/2417
dd29abae4b