Fix "method_complexity" issue in project/main/util_helper.py

[SabCampos]

The file util_helper.py contains a set of functions that are repeated but they are not queries unlike the functions found on same_helper.py

CodeClimate has found the following issue:
Function validaPollutant has a Cognitive Complexity of 57 (exceeds 5 allowed). Consider refactoring.

https://codeclimate.com/github/qAIRa/qAIRaMapAPI-OpenSource/project/main/util_helper.py#issue_614d41560513f9000100002e