Fix gossipsub tests to use `LRUCache` api

[pawanjay176]

Description

Fix test_handle_ihave_subscribed_and_msg_cached in gossipsub tests to use put method of LRUCache over add method of previously used CuckooFilter.

Note: Test doesn't fail if msg_id doesn't exist in the received cache.

[AgeManning]

This already seems to be done?
https://github.com/sigp/rust-libp2p/blob/gossipsub/protocols/gossipsub/src/behaviour/tests.rs#L592

[pawanjay176]

Yup, sorry. I was testing on interop.