Replace inconsistent icon libraries with AsyncAPI design system icons

Background

As part of the icon system audit completed in brand#119, Studio was identified as the primary area of concern. The audit found that Studio currently pulls icons from three different libraries, each with six different viewBox grid sizes, on a single page — none of which align with the AsyncAPI design system standard.

What needs to be done

- Replace inconsistent Studio icons with the correct icons from the AsyncAPI design system
- Use the icon mapping documented in brand#119 as the implementation guide; it shows exactly which icon to replace and what to replace it with

References

Full audit and icon mapping: brand#119

cc @Shurtu-gal @aeworxet