Update filter.ts

[leggechr]

Description:
Remove helpful type at the beginning because it actually was incorrectly returning type never in some cases.

[cartant]

IMO, this change should be accompanied by a failing test that's fixed by the removal of the signature - i.e. something that actually demonstrates the problem.

[MaximSagan]

I would think that if your predicate unconditionally returns false, never would be the correct type

[cartant]

I suspect that predicates that return any will match the first signature, but I'd like to see a failing test that verifies this - especially, as these types of signatures are used elsewhere in the lib.

[cartant]

@leggechr I've added a test that fails if the signature is not removed. If this isn't representative of the code that effected the bug, could you please add a test for that use case, too?

@benlesh This is going to be a problem with any other signatures that also rely upon matching predicates that return false. Any such signatures will need to be removed.

[leggechr]

Hey! Yes that is the correct use case. Thanks for updating.

[benlesh]

@cartant it looks like this problem may exist with first, last, single, takeWhile, and iif

[benlesh]

Related: #5987