Alert Assertion Validation Does not Working as Expected

[haricnugraha]

Describe the bug
Monika crashes when the alert assertion value is invalid.

To Reproduce
Run Monika with the following configuration:

probes:
  - id: '1'
    requests:
      - url: https://github.com
        alerts:
          - assertion: response.size >= 10000 ms
            message: Response size is {{ response.size }}, expecting less than 10000

Expected behavior
Monika gives a message to inform that alert assertion is invalid and stop. In Symon mode, Monika skips the probe that has invalid alert assertion and continues to run other probe.

Screenshots

Desktop (please complete the following information):

• OS: [e.g. Pop!_OS]
• Version [e.g. 22.04]