feat: make pg usage cache timeout configurable

[gagantrivedi]

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Changes

Add env var PG_API_USAGE_CACHE_SECONDS to allow user to set the timeout

How did you test this code?

covered by unit tests

[vercel]

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3 Skipped Deployments

Name	Status	Preview	Comments	Updated (UTC)
docs	⬜️ Ignored (Inspect)			Aug 13, 2024 5:58am
flagsmith-frontend-preview	⬜️ Ignored (Inspect)			Aug 13, 2024 5:58am
flagsmith-frontend-staging	⬜️ Ignored (Inspect)			Aug 13, 2024 5:58am

[sentry-io]

🔍 Existing Issues For Review

Your pull request is modifying functions with the following pre-existing issues:

📄 File: api/app_analytics/cache.py

Function	Unhandled Issue
track_request	RuntimeError: dictionary changed size during iteration /api/v1/ident... Event Count: 15

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[github-actions]

Docker builds report

Image	Build Status	Security report
ghcr.io/flagsmith/flagsmith-e2e:pr-4485	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-api-test:pr-4485	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-frontend:pr-4485	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-api:pr-4485	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-private-cloud:pr-4485	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith:pr-4485	Finished ✅	Results ✅

[github-actions]

Uffizzi Preview deployment-55196 was deleted.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.91%. Comparing base (6660af5) to head (e586b4d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4485   +/-   ##
=======================================
  Coverage   96.91%   96.91%           
=======================================
  Files        1176     1176           
  Lines       39348    39349    +1     
=======================================
+ Hits        38134    38135    +1     
  Misses       1214     1214           

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