The metric monika_probe_result displaying incorrectly

[sapiderman]

Describe the bug
The monika_probe_result metric is stuck on 1 / success

To Reproduce
Steps to reproduce the behavior:

1. Using the following config.yaml

probes:
  - id: 'mock-1'
    name: 'local-test-test'
    requests:
      - url: http://0.0.0.0:7001/v1/hello
    alerts:
      - assertion: response.status < 200 or response.status > 308
        message: HTTP Status is not 200

  - id: 'http-1'
    name: 'status-200-test'
    requests:
      - url: https://httpbin.org/status/200
        method: GET
    alerts:
      - assertion: response.status < 200 or response.status > 308
        message: HTTP Status is not 200
      - assertion: response.time > 2000
        message: Too slow

2. Run monika on npm start -- --prometheus 3001 -c config.yaml
3. Start your target/mock server (mock-1)
4. Go to localhost:3001/metric on your browser
5. After a few minutes disable/turn off the target/mock server (mock-1)

Expected behavior
The metric monika_probe_result should show 0 for a failed probe and 1 for success

Screenshots
both probes running and when mock probe is disabled:

Desktop (please complete the following information):

• OS: Ubuntu LTS 24.04 as WSL on Windows 11
• Version: Monika in main branch / version 1.21.x