IgxInputGroup: font-size too big in fluent design and displayDensity 'compact'

## Description  
The font-size of the IgxInputGroup in fluent design is too big for displayDensity 'compact'.
Here are the current font-sizes for inputs:
- displayDensity 'comfortable': 14px;
- displayDensity 'cosy': 14px;
- displayDensity 'compact': 15.2727px;

 * igniteui-angular version: 15.0.15

## Attachments  
https://stackblitz.com/edit/angular-7z1wyx