feat: start adding support to unsubscribe entity susbcriptions

[Larkooo]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 54 lines in your changes are missing coverage. Please review.

Project coverage is 70.05%. Comparing base (10f7f9f) to head (11f7a6b).
Report is 4 commits behind head on main.

Files	Patch %	Lines
crates/torii/grpc/src/server/mod.rs	0.00%	24 Missing ⚠️
crates/torii/grpc/src/client.rs	0.00%	14 Missing ⚠️
crates/torii/client/src/client/mod.rs	0.00%	10 Missing ⚠️
...ates/torii/grpc/src/server/subscriptions/entity.rs	0.00%	3 Missing ⚠️
...rii/grpc/src/server/subscriptions/event_message.rs	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1857      +/-   ##
==========================================
- Coverage   70.14%   70.05%   -0.10%     
==========================================
  Files         315      315              
  Lines       35607    35657      +50     
==========================================
+ Hits        24977    24979       +2     
- Misses      10630    10678      +48     

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[broody]

LGTM, just minor comment

[Larkooo]

This PR might be closed in favor of dojoengine/dojo.c#25 which uses a client-side approach to close subscription streams. GRPC Will clean up those afterwards.

The problem with the server-side approach is that it adds a bit more complexity than the client-side approach. Doing that server-side involves adding new endpoints for cancelling subscriptions & keeping track of the subscription ID, while the client-side one doesn't have those downsides. The only potential down side is that the subscription cleanup will not be done directly. Only after some time that the stream has closed and gets removed from the GRPC subscriptions