fix: wrong db username causing connection problems

[RMCampos]

Description

Closes no issue.

Errors when deploying database to prod.

On the backend:

In the database:

Also, PROD deployments failing, more here: https://github.com/bcgov/nr-spar/actions/runs/9719572000

Changelog

New

• None;

Changed

• Postgres DB connection Username on Dockerfile;

Removed

• None;

How was this tested?

• [ ] 🧠 Not needed
• [x] 👀 Eyeball
• [ ] 🤖 Added tests

What gif/image best describes this PR or how it makes you feel?

---

Thanks for the PR!

Deployments, as required, will be available below:

• Frontend
• Backend
• Oracle-API

Please create PRs in draft mode. Mark as ready to enable:

• Analysis Workflow

After merge, new images are deployed in:

• Merge Workflow

---

Thanks for the PR!

Deployments, as required, will be available below:

• Frontend
• Backend
• Oracle-API

Please create PRs in draft mode. Mark as ready to enable:

• Analysis Workflow

After merge, new images are deployed in:

• Merge Workflow