Empty string can end up in the Fuels json quantity field

[pbastia]

Describe the Bug:

If a reporter, on their application:

• adds a new fuel
• enters the emission category
• enters the fuel name
• closes the browser window without any other action

then this JSON ends up in the form data:

  {
    "quantity": "",
    "fuelRowId": 13,
    "fuelUnits": "t",
    "emissionCategoryRowId": 1
  }

which causes the validation functions and the CIIP Fuel view to misbehave, and prevents access to the application for the user to fix the issue.

Probability (1-5): 3

Effect (1-5): 5

Steps to reproduce the behaviour:

Screenshots:

Additional information:

• OS: [e.g. iOS]
• Browser: [e.g. chrome, safari]
• Version: [e.g. 22]
• Additional context