bpf: Migrate bpf_task_work_schedule_* kfuncs to KF_IMPLICIT_ARGS

bpf: Migrate bpf_task_work_schedule_* kfuncs to KF_IMPLICIT_ARGS

Implement bpf_task_work_schedule_* with an implicit bpf_prog_aux
argument, and remove corresponding _impl funcs from the kernel.

Update special kfunc checks in the verifier accordingly.

Update the selftests to use the new API with implicit argument.

Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-10-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>