Fix populateDataNodeConfig to return true for no-op

[crliao]

Summary

• fixing Populate instance config and data node config during server startup #3188 to return true for populateDataNodeConfig when no-op, to avoid error logging

Testing Done

• gha

[codecov-commenter]

Codecov Report

❌ Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.80%. Comparing base (52ba813) to head (e0f8265).
⚠️ Report is 336 commits behind head on master.

Files with missing lines	Patch %	Lines
...y/clustermap/RecoveryTestClusterAgentsFactory.java	0.00%	1 Missing ⚠️
...b/ambry/clustermap/StaticClusterAgentsFactory.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3191      +/-   ##
============================================
+ Coverage     64.24%   69.80%   +5.56%     
- Complexity    10398    12811    +2413     
============================================
  Files           840      930      +90     
  Lines         71755    79054    +7299     
  Branches       8611     9455     +844     
============================================
+ Hits          46099    55184    +9085     
+ Misses        23004    20930    -2074     
- Partials       2652     2940     +288     

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