Add nil hash validation

[AnkushinDaniil]

Fix #2239
Continue #2290

Protocol Buffer Validation:

• p2p/spec/common.proto: Added import for buf/validate/validate.proto and added a required field validation to message Hash. [1] [2]
• p2p/sync/client.go: Integrated protovalidate for validating protocol buffer messages in the requestAndReceiveStream function. [1] [2] [3]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.63%. Comparing base (0c6508c) to head (56d5310).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2296      +/-   ##
==========================================
- Coverage   74.69%   74.63%   -0.07%     
==========================================
  Files         110      110              
  Lines       12109    12109              
==========================================
- Hits         9045     9037       -8     
- Misses       2366     2372       +6     
- Partials      698      700       +2     

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[pnowosie]

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[rodrigo-pino]

What does using buf in this PR is improving over not using buf?

Would adding buf means an extra dependency to compile Juno successfully or just for development? Should the use of buf be documented somewhere as dependency?

Some questions, trying to understand the code base

[AnkushinDaniil]

What does using buf in this PR is improving over not using buf?

Because we need to import "buf/validate/validate.proto";, which is external proto. protoc requires all proto files to be in the project.

Would adding buf means an extra dependency to compile Juno successfully or just for development? Should the use of buf be documented somewhere as dependency?

This is for development only. buf and protoc are tools that allow you to generate go files from proto files. The main difference is that buf generates remotely and has a more convenient configuration.