fix(webhook/changed_by): Return name of the master api key

[gagantrivedi]

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Changes

Return name of the master api_key if the change was made using it instead of empty string

How did you test this code?

test cases updated

[vercel]

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Name	Status	Preview	Comments	Updated (UTC)
docs	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Sep 9, 2024 0:28am

2 Skipped Deployments

Name	Status	Preview	Comments	Updated (UTC)
flagsmith-frontend-preview	⬜️ Ignored (Inspect)	Visit Preview		Sep 9, 2024 0:28am
flagsmith-frontend-staging	⬜️ Ignored (Inspect)	Visit Preview		Sep 9, 2024 0:28am

[github-actions]

Docker builds report

Image	Build Status	Security report
ghcr.io/flagsmith/flagsmith-api-test:pr-4602	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-e2e:pr-4602	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-frontend:pr-4602	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-api:pr-4602	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith:pr-4602	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-private-cloud:pr-4602	Finished ✅	Results ✅

[github-actions]

Uffizzi Preview deployment-56023 was deleted.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.16%. Comparing base (b2a1899) to head (6d1b9ae).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4602   +/-   ##
=======================================
  Coverage   97.15%   97.16%           
=======================================
  Files        1157     1157           
  Lines       40023    40037   +14     
=======================================
+ Hits        38886    38900   +14     
  Misses       1137     1137           

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