refactor(shwap/p2p/shrex): remove rate limiting middleware

[renaynay]

Firstly, I need this branch for shrex-nd load testing. Related to https://github.com/celestiaorg/celestia-node/issues/4331 and https://github.com/celestiaorg/celestia-node/issues/4236.

Second, after speaking with @walldiss about the middleware, I think either a full removal (here in this PR) or at least an option to disable the rate limiting middleware is in order.

I opted for full removal as the change is not invasive and does not demand for us to add more LOC - and it would be easy to revert in the case we need to re-add it.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 34.96%. Comparing base (2469e7a) to head (4cd0c1d). Report is 507 commits behind head on main.

Files with missing lines	Patch %	Lines
share/shwap/p2p/shrex/shrexnd/client.go	0.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4333      +/-   ##
==========================================
- Coverage   44.83%   34.96%   -9.87%     
==========================================
  Files         265      316      +51     
  Lines       14620    24702   +10082     
==========================================
+ Hits         6555     8638    +2083     
- Misses       7313    15135    +7822     
- Partials      752      929     +177     

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