[Jaeger-Agent] Use RawConn.Control to get fd instead of Fd()

[ChenX1993]

Which problem is this PR solving?

Resolves #4448

Short description of the changes

Jaeger agent gets stuck when closing with SocketBufferSize set. This is because Close() of net.UDPConn will be blocked if Fd() is used to get the file descriptor.
Use RawConn.Control instead to get fd to set the socket buffer.

Same issue was discussed here: golang/go#29277
The fix refers to here: brucespang/go-tcpinfo#3

[codecov]

Codecov Report

Patch coverage: 46.15% and project coverage change: -0.03 ⚠️

Comparison is base (5c3c20d) 97.07% compared to head (1e3ab01) 97.05%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4449      +/-   ##
==========================================
- Coverage   97.07%   97.05%   -0.03%     
==========================================
  Files         300      300              
  Lines       17728    17738      +10     
==========================================
+ Hits        17210    17215       +5     
- Misses        416      419       +3     
- Partials      102      104       +2     

Flag	Coverage Δ
unittests	97.05% <46.15%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
cmd/agent/app/servers/thriftudp/socket_buffer.go	43.75% <46.15%> (-6.25%)	⬇️

... and 1 file with indirect coverage changes

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[yurishkuro]

please make sure commits are signed

[ChenX1993]

please make sure commits are signed

Signed