[Bug]: AssertionError when dealing with unnamed parameters

[glarregay-tob]

Describe the issue:

If you want to print a parameter name, and the parameter is unnamed, you get:

Traceback (most recent call last):
  File "<stdin>", line 3, in <module>
  File "/opt/homebrew/lib/python3.11/site-packages/slither/core/variables/variable.py", line 182, in __str__
    assert self._name
AssertionError

Code example to reproduce the issue:

Contract:

//SPDX-License-Identifier: UNLICENSED

pragma solidity 0.8.10;

contract TestSlither {
    function test_function(uint256 param1, uint256, address param3) public {
        
    }
}

Script:

from slither import Slither

s = Slither("poc.sol")
c = s.contracts[0]

for f in c.functions:
    for p in f.parameters:
        print(p)

Version:

0.9.6

Relevant log output:

No response

[0xalpharush]

We can change this to be optional and remove the assertion