[Issue #1123] Fix LwM2M example for Gateway

[Chi-Kai]

What this PR does / why we need it:

Will this PR make the community happier?

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

How is this PR tested

• unit test
• e2e test
• other (please specify)

Special notes for your reviewer:

Release note:

Apologies, I have already revised the commit history.

[rhoninl]

LGTM

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 33.20%. Comparing base (eb8ea86) to head (c0ab0f7).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1142      +/-   ##
==========================================
+ Coverage   33.10%   33.20%   +0.10%     
==========================================
  Files          55       55              
  Lines        4864     4864              
==========================================
+ Hits         1610     1615       +5     
+ Misses       3114     3110       -4     
+ Partials      140      139       -1     

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[tomqin93]

@Chi-Kai Thanks for this PR! Please reach out to info@edgenesis.com for a bag of goodies :)