Making 'Become a Mentor' form to validate number as input value #196

[shiv-0101]

Purpose

The contact number field was not validating input properly. It was accepting strings or any unfair input, allowing the user to go to the next step without proper validation.

The purpose of this PR is to fix #196

Goals

Goal was to change 'text' to 'number'

Approach

Updated the input text value from 'text' to 'number' so that only number can be passed and user can move to next step.

Checklist

• [✅] This PR doesn't commit any keys, passwords, tokens, usernames, or other secrets.
• [✅ ] I have read and understood the development best practices guidelines ( http://bit.ly/sef-best-practices )
• [✅ ] My code follows the style guidelines of this project
• [✅] I have performed a self-review of my own code
• [✅ ] I have commented my code, particularly in hard-to-understand areas
• [✅ ] I have made corresponding changes to the documentation