chore: add execution stats header to the ut response

[abhimanyubabbar]

What are the changes introduced in this PR?

We are adding two new headers only in the response to the /customTransform call in the user-transformer service.

The two headers and there format are as follows:

1. X-Response-Time:105.23ms
2. X-Instance-ID:<instance-id>/<worker-id>

In case the system is unable to determine the instance-id and worker-id from the env it will use the value default for the instance-id and master for the worker-id. So overall the valud of the X-Instance-ID will be default/master

What is the related Linear task?

Resolves DAT-1713

Please explain the objectives of your changes below

Put down any required details on the broader aspect of your changes. If there are any dependent changes, mandatorily mention them here

Any changes to existing capabilities/behaviour, mention the reason & what are the changes ?

N/A

Any new dependencies introduced with this change?

N/A

Any new generic utility introduced or modified. Please explain the changes.

N/A

Any technical or performance related pointers to consider with the change?

N/A

@coderabbitai review

---

Developer checklist

• My code follows the style guidelines of this project

• No breaking changes are being introduced.

• All related docs linked with the PR?

• All changes manually tested?

• Any documentation changes needed with this change?

• Is the PR limited to 10 file changes?

• Is the PR limited to one linear task?

• Are relevant unit and component test-cases added in new readability format?

Reviewer checklist

• Is the type of change in the PR title appropriate as per the changes?

• Verified that there are no credentials or confidential data exposed with the changes.

[devops-github-rudderstack]

Test report for this run is available at: https://test-integrations-dev.s3.amazonaws.com/integrations-test-reports/rudder-transformer/3882/test-report.html

[sonarqubecloud]

Quality Gate passed

Issues
20 New issues
1 Accepted issue

Measures
0 Security Hotspots
93.4% Coverage on New Code
0.3% Duplication on New Code

See analysis details on SonarQube Cloud

[devops-github-rudderstack]

This PR is considered to be stale. It has been open for 20 days with no further activity thus it is going to be closed in 7 days. To avoid such a case please consider removing the stale label manually or add a comment to the PR.

[devops-github-rudderstack]

Allure Test reports for this run are available at:

• Allure Report: https://rudderlabs.github.io/rudder-transformer/65/index.html

[devops-github-rudderstack]

Allure Test reports for this run are available at:

• Allure Report: https://rudderlabs.github.io/rudder-transformer/66/index.html

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 90.75%. Comparing base (e8bc593) to head (6463e85).
Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/middlewares/stats.ts	33.33%	6 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3882      +/-   ##
===========================================
- Coverage    90.77%   90.75%   -0.02%     
===========================================
  Files          624      625       +1     
  Lines        32556    32566      +10     
  Branches      7731     7733       +2     
===========================================
+ Hits         29552    29556       +4     
+ Misses        2780     2754      -26     
- Partials       224      256      +32     

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[devops-github-rudderstack]

Allure Test reports for this run are available at:

• Allure Report: https://rudderlabs.github.io/rudder-transformer/126/index.html

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud