If Monkey agent binaries are missing, Monkey Island shows no indication

[ShayNehmad]

Describe the bug
When the Monkey agent binary is missing, the Island shows no clear indication as to WHY it is failing to run, instead only producing this log:

2019-11-10 16:12:16,361 - local_run.py:41 - run_local_monkey() - ERROR - Copy file failed
Traceback (most recent call last):
  File "/var/monkey_island/monkey_island/cc/resources/local_run.py", line 38, in run_local_monkey
    copyfile(monkey_path, target_path)
  File "/home/user/projects/monkey/lib/python3.6/shutil.py", line 120, in copyfile
    with open(src, 'rb') as fsrc:
FileNotFoundError: [Errno 2] No such file or directory: '/var/monkey_island/monkey_island/cc/binaries/monkey-linux-64'
2019-11-10 16:12:16,361 - wsgi.py:196 -       _log() - INFO - 200 POST /api/local-monkey (::1) 1.63ms

To Reproduce
Steps to reproduce the behavior:

1. Set up Monkey Island without the Monkey Binaries
2. Press "Run on Monkey Island"
3. Nothing happens
4. See error in logs

Expected behavior
The Island should pop up an error message to the user explaining what happened and how to fix it/contact us.

Screenshots/logs

2019-11-10 16:12:16,361 - local_run.py:41 - run_local_monkey() - ERROR - Copy file failed
Traceback (most recent call last):
  File "/var/monkey_island/monkey_island/cc/resources/local_run.py", line 38, in run_local_monkey
    copyfile(monkey_path, target_path)
  File "/home/user/projects/monkey/lib/python3.6/shutil.py", line 120, in copyfile
    with open(src, 'rb') as fsrc:
FileNotFoundError: [Errno 2] No such file or directory: '/var/monkey_island/monkey_island/cc/binaries/monkey-linux-64'
2019-11-10 16:12:16,361 - wsgi.py:196 -       _log() - INFO - 200 POST /api/local-monkey (::1) 1.63ms

Thanks @liad-guardicore for letting us know