Crash in `binary_pattern_matching` due to missing ELF path

[krpandrei05]

• The generate command using the binary_pattern_matching heuristic crashes with a TypeError when the required --elf option is omitted.
• The CLI should validate the presence of this argument and provide a clear error message instead of failing or producing an empty result.
• The result is:

$ poetry run attack_surface_approximation generate --heuristic binary_pattern_matching --output examples/dictionaries/ex3.txt 
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation_original/attack_surface_approximation/cli.py", line 194, in main
    cli(prog_name="attack_surface_approximation")
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation/.venv/lib/python3.12/site-packages/click/core.py", line 1514, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation/.venv/lib/python3.12/site-packages/click/core.py", line 1435, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation/.venv/lib/python3.12/site-packages/click/core.py", line 1902, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation/.venv/lib/python3.12/site-packages/click/core.py", line 1298, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation/.venv/lib/python3.12/site-packages/click/core.py", line 853, in invoke
    return callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation_original/attack_surface_approximation/cli.py", line 58, in generate
    generator.generate(heuristic, elf)
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation_original/attack_surface_approximation/dictionaries_generators/generator.py", line 63, in generate
    self.arguments = heuristic_module.generate(elf)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/krpandrei/andreiOpenCRS/attack_surface_approximation_original/attack_surface_approximation/dictionaries_generators/heuristics/binary_pattern_matching.py", line 8, in generate
    content = open(elf, "rb").read()
              ^^^^^^^^^^^^^^^
TypeError: expected str, bytes or os.PathLike object, not NoneType