internal: drop unused NeoFS SDK-related code

[AnnaShaleva]

#2477 is closed long time ago, I suppose this code is irrelevant anymore.

Ref. nspcc-dev/neo-go#3757 (comment).

[AnnaShaleva]

This change likely shouldn't be reflected in the CHANGELOG because it's not a user-facing thing.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 22.44%. Comparing base (474d541) to head (09156fd).
Report is 82 commits behind head on master.

Files with missing lines	Patch %	Lines
cmd/neofs-cli/internal/client/sdk.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3054      +/-   ##
==========================================
+ Coverage   22.43%   22.44%   +0.01%     
==========================================
  Files         791      791              
  Lines       58381    58369      -12     
==========================================
+ Hits        13096    13100       +4     
+ Misses      44386    44371      -15     
+ Partials      899      898       -1     

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[cthulhu-rider]

the hack is still relevant cuz we keep using API (SN) client to dial IR. #2477 was closed as unplanned since this should be resolved another way

at the same time, this is a good reminder: with the next SDK upgrade IR will stop using the API client. So, i wont close the PR for now, the code block is easy-to-forget

[roman-khimov]

Red one. I'd say that control service client is just a different client, it shouldn't reuse SDK client. But that's a different story.

[carpawell]

Can this be rebased and tried one more time after the latest PR?

[roman-khimov]

Included into #3103.