Update Android Executorch example (Image Segmentation) documentation accounting for the newly added feature

[psiddh]

📚 The doc issue

This will help the users to check images segmentation feature for the dynamically added images, w/o having to recompile the entire Android apk or the need for Android studio.

Suggest a potential alternative/fix

No response

cc @mergennachin @iseeyuan @lucylq @helunwencser @tarun292 @kimishpatel @jackzhxng

[psiddh]

pytorch-labs/executorch-examples#38