[Form Validation] Hidden Required fields should not be validated

[dubdabasoduba]

Describe the bug

• Currently, when a field on the Questionnaire is hidden the Required validation check is still applied to it.
• This means the user will get an error prompting them to fill all required fields. The user is however not able to fill in the field since it's hidden.

To Reproduce
Steps to reproduce the behaviour:

1. Add a Required field in a questionnaire.
2. Fill up the questionnaire and try to submit it.
3. An error asking the user to confirm that all the fields were filled up will be thrown.

Expected behaviour

• All visible required fields should be validated
• All hidden required fields should not be validated on submission.

General Implementation Idea

• We should not validate any field when the value of the hidden extension is set to true
  • This means we first check for the hidden extension and then run validation on the field.

Assumption

• Skip Logic also uses the hidden extension to also hide/show fields.

Screenshots
https://user-images.githubusercontent.com/4817531/188339502-7f9d17a0-7292-4412-ba86-bc97687e985d.mp4

Hidden field JSON

{
  "linkId": "83943853-d9c9-46ad-da39-2cc55e93b974",
  "type": "integer",
  "text": "Birth weight",
  "required": true,
  "extension": [
    {
      "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-hidden",
      "valueBoolean": true
    }
  ]
}

Smartphone (please complete the following information):

• Device: Emulator & Xiaomi 11T Pro
• Android version: 10 & 12

Related SDK Issue

• [Form Validation] Hidden Required fields should not be validated #1579

[maimoonak]

Done in PR #1610 . The validator would not perform any validation on hidden fields.