Fix: Added md breakpoint in the modal dialog in _modal.scss #40591

[poswalsameer]

Description

Fixes Issue #40591

Added md breakpoint in the modal dialog in _modal.scss file.

Motivation & Context

Adds responsiveness to screen ranging in the size between sm and lg.

Type of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ x] New feature (non-breaking change which adds functionality)
• [ x] Refactoring (non-breaking change)
• [ ] Breaking change (fix or feature that would change existing functionality)

Checklist

• [ x] I have read the contributing guidelines
• [ x] My code follows the code style of the project (using npm run lint)
• [ ] My change introduces changes to the documentation
• [ ] I have updated the documentation accordingly
• [ ] I have added tests to cover my changes
• [ x] All new and existing tests passed