Modify metrics example to shutdown without global shutdown method

[cijothomas]

To see if we need to keep global::shutdown() for metrics.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.3%. Comparing base (348ec9e) to head (51a0b80).
Report is 13 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1739     +/-   ##
=======================================
+ Coverage   71.0%   71.3%   +0.3%     
=======================================
  Files        135     136      +1     
  Lines      20751   20840     +89     
=======================================
+ Hits       14746   14877    +131     
+ Misses      6005    5963     -42     

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[TommyCpp]

IIRC we never introduce the behavior that requires all loggers(meters for metrics) to be dropped before one can allow shutdown so it should work