Component: InputGroup - incorrect presentation using icon only button

[badylq]

Describe the bug

InputGroup works incorrectly when addon is button with icon and no text. Bug can be seen in PrimeNG documentation page https://primeng.org/inputgroup#button where first group is displayed correctly and 2 other have gaps above and below button. It's most visible when using Material style with soho surface, but it is present in any preset/color combo.

Environment

dev/documentation

Reproducer

No response

Angular version

18.2.13

PrimeNG version

18.0.0

Build / Runtime

Angular CLI App

Language

TypeScript

Node version (for AoT issues node --version)

v20.15.1

Browser(s)

Chrome 131.0.6778.86

Steps to reproduce the behavior

No response

Expected behavior

Filled button without gaps like when there is only text