Adopt a more liberal approach for TwigValidatorRuleTestExpr

I was getting this warning with a test like if variable is defined. In my case, I wanted the condition to be true if variable was zero. That would not be the case if I had used if variable.

From Liam in 🐛 The "empty is not needed" test is not correct Active

This condition: {% if variable is not empty %}
raised the warning "The exact same as just testing the variable, empty is not needed."

But if I switched it to: {% if variable %}
then the condition would fail if variable was zero.

Let's check if empty is really same as just testing the variable before setting our "liberal" list of warnings.

Some references:

• Twig tests: https://twig.symfony.com/doc/3.x/tests/index.html
• Jinja tests: https://jinja.palletsprojects.com/en/stable/templates/#list-of-builtin-t...

I am not sure to get the whole scope of changes and result expected here, could we be more clear and give testable examples:

{% set variable = '' %}
{% if variable is not empty %}{% endif %}

=> Warning

{% set variable = [] %}
{% if variable is not empty %}{% endif %}

=> Warning

{% set variable = 0 %}
{% if variable is not empty %}{% endif %}

=> No warning

{% set variable = null %}
{% if variable is not empty %}{% endif %}

=> ?

{% set variable = true %}
{% if variable is not empty %}{% endif %}

=> ?

{% set variable = false %}
{% if variable is not empty %}{% endif %}

=> ?

{% set variable = injected_variable %}
{% if variable is not empty %}{% endif %}

=> From previous rules based on type of injected variable?

{% set variable = set_variable_before %}
{% if variable is not empty %}{% endif %}

=> Probably hard to detect as the vriable is set in the template.

ok i will work on clarifying the scope