add BoxWithNMSLimit_out to DSP as a custom portable op

Summary:
Callsite: https://www.internalfb.com/code/fbsource/[3c01ebf76a180e7f6b5ddd8e50f4be695d85180f]/fbcode/vizard_projects/midas_haptic/model/haptic.py?lines=509-532
Reference implementation: https://www.internalfb.com/code/fbsource/fbcode/caffe2/fb/custom_ops/maskrcnn/box_with_nms_limit.cpp

This op will be migrated and supported by ExecuTorch as a portable op in the future.

Differential Revision: D72275947

Author: zonglinpeng

runtime/core/portable_type/c10/c10/targets.bzl

@@ -36,6 +36,7 @@ def define_common_targets():
         ]),
         visibility = [
             "//executorch/...",
+            "@EXECUTORCH_CLIENTS",
         ],
         deps = select({
             "DEFAULT": [],