Checklist:

• I have read and followed the contribution guidelines.
• I have read and followed the how to open a pull request guide.
• My pull request targets the main branch of the repo.
• I have tested these changes locally on my machine.

Moves the code analysis and unit tests to a separate workflow.

I initially tried splitting them into 2 jobs, and having unit-tests depends on analyze:

jobs:
  analyze:
    steps:
      - checkout
      - setup flutter
      - install dependencies
      - setup .env
      - flutter analyze
  unit-tests:
    needs: analyze
    steps:  
      - checkout
      - setup flutter
      - install dependencies
      - setup .env
      - flutter test

But the flutter setup and deps installation takes a lot longer than the time to run the unit tests, so it wasn't worth it and I decided to just merge them into a single job.