samples: cmsis_rtos_v1: philosophers: skip up_squared

The up_squared board suffers the same issue as qemu_x86_64
where a bigger stack is needed but CMSIS has a limit on
how big the stack can be. This results in stack overflow.

So exclude up_squared in samples.yaml.

Fixes #28552

Signed-off-by: Daniel Leung <daniel.leung@intel.com>