chore: Setting environment var DD_LOGS_INJECTION=true for Django app deployments

[nadeemshahzad]

This PR adds the environment variable DD_LOGS_INJECTION=true to app deployments. By enabling this setting, Python logs will can be correlated with Datadog traces, allowing for enhanced visibility and easier troubleshooting within the Datadog platform.
https://2u-internal.atlassian.net/browse/GSRE-1687

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Make sure that the following steps are done before merging:

• Have a Site Reliability Engineer review the PR if you don't own all of the services impacted.
• If you are adding any new default values that need to be overridden when this change goes live, update internal repos and add an entry to the top of the CHANGELOG.
• Performed the appropriate testing.