Update Gleam icon (#19978)

Jen Stehlik created 

Improves upon: https://github.com/zed-industries/zed/pull/19887

Implements the feedback by @PixelJanitor to make the icon follow the
design guidelines.

Release Notes:

- Improved Gleam icon

Change summary

assets/icons/file_icons/gleam.svg | 1 -
1 file changed, 1 deletion(-)

Detailed changes