pillar/tests: Adapt tests for ARM and FML OVMF firmware.

Adapt the existing tests to account for the addition of the OVMF
settings file for FML guests, ensuring the expected output includes the
BootLoader. It also fixes the ARM tests by ensuring the firmware line is
present in the expected configuration, aligning the tests with the
updated behavior for UEFI boot on both AMD64 and ARM architectures.

Signed-off-by: Nikolay Martyanov <nikolay@zededa.com>