Improve 'prevent-addEventListener' — save reference to 'toString()' method

[AdamWr]

If website overrides Function.prototype.toString then prevent-addEventListener might not works.
Related to - AdguardTeam/AdguardFilters#143847

---

Steps to reproduce:

1. Add this rule:

example.org#%#//scriptlet('prevent-addEventListener', '', 'alert')

2. Go to - https://example.org/
3. In browser console run:

const nativeToString = Function.prototype.toString;
Function.prototype.toString = function (arg) {
  return nativeToString.call(this).includes('alert')
    ? ""
    : nativeToString.call(this);
};
document.documentElement.addEventListener('click', () => {
  alert(1);
});

4. Click somewhere

Alert should be prevented by prevent-addEventListener rule, but it doesn't work.

We probably could just save reference to Function.prototype.toString and use it in listenerToString

Scriptlets/src/helpers/add-event-listener-utils.js

Lines 39 to 43 in b1e0bda

	export const listenerToString = (listener) => {
	return typeof listener === 'function'
	? listener.toString()
	: listener.handleEvent.toString();
	};

Something like:

const nativeToString = Function.prototype.toString;
nativeToString.call(listener);