Update logo.svg with new design and optimized dimensions (#1719)

Replace the existing activity bar icon with a new design more aligned
with the wider codicon design language.


![image.png](https://github.com/user-attachments/assets/65b0c66b-0e1a-4610-89d7-94206fafa044)

Co-authored-by: mrleemurray <mrleemurray@users.noreply.github.com>

Author: mrleemurray