The subgraph `getGroups` function returns wrong members

[vplasencia]

Description

If there are two members in an on-chain Semaphore group and one of the members is removed, the getGroup function from the SemaphoreSubgraph class returns the old value of the member instead of the new value that should be 0.

It looks like the function does not take into account when a member is removed (probably also when the member is updated).

[AjayAdsule]

@vplasencia should i work on it, if yes please assign to me

[vplasencia]

Hey @AjayAdsule! Feel free to start working on it.

[vplasencia]

Hey @AjayAdsule! This is a priority task now and should be solved asap before ETHIndia. Then I will assign this task to someone who will start to work on it now. Sorry about it but please, feel free to pick any other issues you like.

[waddaboo]

@vplasencia Hey! I can work on it, can you assign it to me? Thanks in advance!