[Task]: Implement LRU caching to cache and evict mock mongoDB connections

[NilanshBansal]

SubTasks

Reason: We have recently seen a surge in the number of connections to the mongo movies mockDB leading to the max limit reached.
This directly impacted the cypress tests and the usage of the mockDB for the release, prod and self hosted instances.

On debugging we found the mockDB connections were not getting closed, hence to resolve this we need to implement the LRU caching for the mockDB connections and close the least recently used connections.

Ref: https://theappsmith.slack.com/archives/C02MUD8DNUR/p1726855216593569?thread_ts=1725892395.532789&cid=C02MUD8DNUR
Earlier findings here: https://app.zenhub.com/workspaces/query--js-pod-6322a759b3296d249ce5c4ed/issues/zh/238