eSignet<>Thunder: Add Backend Regex and Length Validations in Thunder backend for UI Form Fields

[rachik-hue]

Purpose

As a developer, I want to add backend validations for regex patterns and field length constraints for UI form fields, so that invalid data is consistently prevented and validated irrespective of client-side validation behavior.

Design And Implementation:

Validations in the executors.

• Way to pass the regex or length configuration from user schema or from flow json.
• Support for below input type fields

Text Input - Multi Lang, support for the regex validations
Dropdown - Already added
Date - Pattern/format validations to be added

Please refer the below for more details:

1. Issue - Support Input Validation for Flow Inputs thunder-id/thunderid#2619
2. Discussion - [Design Discussion] Input Validation for Flow Inputs thunder-id/thunderid#2410