Update stac-api DB_MAX_CONN_SIZE to match AKS deployment

[karthick-rn]

Description

During the availability issue when pgbouncer was enabled we updated this property to fix the issue. This PR was to capture the update to match the value in the repo.

Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

Checklist:

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• I have performed a self-review
• Changelog has been updated
• Documentation has been updated
• Unit tests pass locally (./scripts/test)
• Code is linted and styled (./scripts/format)