fix: check domains validity when parsing network filters

[seia-soto]

From #4524, I found that NetworkFilter.prototype.toString is broken for network modifiers utilizing Domains.

This fixes it by replacing all , into | in Domains.parts.

Also, this moves invalid option value check which was used to prevent passing $domain=|a.com| forms into Domains.prototype.parse.

[chrmod]

can we add some tests for those changes?

[seia-soto]

@chrmod Added 96f51b8 (#4525)

[seia-soto]

@chrmod I realized that it was improper to add a check in the Domains.prototype.parse since it was also used by cosmetics. Instead, I created a separate function called #normalizeNetworkEntities to do this. Also, new change includes:

• Tests for #normalizeNetworkEntities and NetworkFilter.prototype.toString

[seia-soto]

Tests are currently expected to fail: see #4525 (comment)

[seia-soto]

One more idea to this would be having a Domains.prototype.toString method and accept isNetworkFilter = false as a first argument.

[chrmod]

Wouldn't it make more sense to move the splitting to Domain.parse and pass a desired separator as an argument?

The logic for the trailing | may apply to trailing ,.

Or alternatively, we could ignore those trailing characters as filters that include them (if they exist) may still be useful. The question is how fault tolerant we want to be. Eg. Should we drop filter: test$domain=example.com|example.org||

[seia-soto]

@chrmod I believe adblocker should not be error tolerant here.

• We had a test that reject those typos
• Those typo happens only if a filter maintainer is developing a filter

For the dynamic delimiter, I agree that we can just accept the string instead of boolean flag.