Dev: Investigate why apps become unavailable during deployments

**Actual Behaviour**

For a short period of time during deployments, our apps become unavailable - 404

**Steps To Reproduce**

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**Screenshots**

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**Expected Behaviour**

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https://bcps-wps.sentry.io/issues/7117228031/events/603c39a4de04433aae2912a98ec7d579/

Review the linked Sentry event and the deployment process to determine why applications return 404 responses for a short period during deployments. The issue provides no named files or tests, so first identify the relevant deployment entry points and reproduce or observe the failure. Done means deployments no longer make the applications temporarily unavailable.

Written by the indexing model from the issue text.