number() should return null instead of failing the evaluation

[saig0]

Describe the bug
I use the function number() to convert a string into a number. If the string is not a number then the evaluation fails.

An evaluation failure is unexpected and it doesn't allow to handle this case.

To Reproduce
Steps to reproduce the behavior:

1. Evaluate the expression

number("x")

2. Verify that the evaluation fails

Expected behavior
The function should return null if the string is not a valid number.

See the TCK test case 0058-feel-number-function.

Environment

• FEEL engine version: 1.17.0
• Affects:
  • Camunda Automation Platform 7: [7.x]
  • Zeebe broker: [0.x]

Related to #623