feat: remove filter.subscribe() dependency on IReceiver

[danisharora099]

Problem

IReceiver currently expects subscribe() to be a function on the class implementation that we previously used for Filter. We moved to createSubscription() method instead, which is more generic.

Proposed Solutions

Remove the dependency which should allow us to remove the subscribe() implementation from Filter, and can just exist in the Subscription class instead

Notes

[weboko]

note: it is possible to remove .subscribe but we have to keep .toSubscriptionIterator to support js-noise

https://github.com/waku-org/js-noise/blob/44d0eecbfbf13eb9c69fadd05fa4494cff31229c/src/pairing.ts#L229

[danisharora099]

note: it is possible to remove .subscribe but we have to keep .toSubscriptionIterator to support js-noise

https://github.com/waku-org/js-noise/blob/44d0eecbfbf13eb9c69fadd05fa4494cff31229c/src/pairing.ts#L229

Perfect. toSubscriptionIterator can remain part of SDK, and we can remove the subscribe() dependency from Core