examples: fix debugging example after Dial->NewClient migration

[dfawley]

This addresses a comment in #7049.

The manual package's UpdateState method cannot be used until after a client attempts to connect. Maybe that behavior should be change, but this example really wants to use InitialState anyway. Also, make the client and server listen on different ports for channelz, so they can both run at the same time.

RELEASE NOTES:

• examples: fix the debugging example

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.92%. Comparing base (274830d) to head (e9f8e11).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7833      +/-   ##
==========================================
+ Coverage   81.90%   81.92%   +0.01%     
==========================================
  Files         374      374              
  Lines       37978    37978              
==========================================
+ Hits        31105    31112       +7     
+ Misses       5579     5572       -7     
  Partials     1294     1294              

see 22 files with indirect coverage changes