[feat][backend]: refactor offline metrics

[kidkidkid]

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[codecov]

Codecov Report

❌ Patch coverage is 81.60000% with 23 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ervability/domain/metric/service/offline_metric.go	86.53%	11 Missing and 3 partials ⚠️
...ackend/modules/observability/application/metric.go	50.00%	3 Missing and 4 partials ⚠️
...ules/observability/domain/metric/service/metric.go	71.42%	1 Missing and 1 partial ⚠️

@@            Coverage Diff             @@
##             main     #367      +/-   ##
==========================================
+ Coverage   69.48%   69.58%   +0.09%     
==========================================
  Files         616      616              
  Lines       58135    58197      +62     
==========================================
+ Hits        40397    40498     +101     
+ Misses      14775    14719      -56     
- Partials     2963     2980      +17     

Flag	Coverage Δ
unittests	69.58% <81.60%> (+0.09%)	⬆️

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

Files with missing lines	Coverage Δ
...ules/observability/domain/metric/service/metric.go	60.61% <71.42%> (+1.89%)	⬆️
...ackend/modules/observability/application/metric.go	69.75% <50.00%> (-2.44%)	⬇️
...ervability/domain/metric/service/offline_metric.go	86.84% <86.53%> (+19.53%)	⬆️

... and 2 files with indirect coverage changes

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