Fixed the overflowed signup screen

[Samdid]

Related Issue

-Sign up screen is overflowing so there is need to fix it

Closes: #68

Describe the changes you've made

I have fixed the overflowing sign up screen by adding Singlechildscrollview widget and reducing the height of textfields

Type of change

What sort of change have you made:

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Code style update (formatting, local variables)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Mention any unusual behaviour of your code (Write NA if not)

Any unusual behaviour of your code

Checklist:

• [x] My code follows the guidelines of this project.
• [x] I have performed a self-review of my own code.
• [ ] I have commented my code, particularly whereever it was hard to understand.
• [x] My changes generate no new warnings.
• [ ] Any dependent changes have been merged and published in downstream modules.

Additional Info (optional)

Any additional information you want to give Screenshot:

[Samdid]

@hiashutoshsingh Changes resolved