icons: Remove ZedAssistant2 icon (#27634)

This PR removes the `ZedAssistant2` icon.

I went to use it as a placeholder icon, but noticed that the icon wasn't
loaded properly due to a name mismatch.

However, since we aren't using it anywhere I'm opting to remove it.

Release Notes:

- N/A

assets/icons/zed_assistant_2.svg

@@ -1,5 +0,0 @@
-<svg width="14" height="14" viewBox="0 0 14 14" fill="none" xmlns="http://www.w3.org/2000/svg">
-<path d="M5.27772 1.38585L4.39187 4.07909C4.34653 4.21692 4.26946 4.34219 4.16685 4.44479C4.06425 4.5474 3.93898 4.62447 3.80115 4.66981L1.10791 5.55566L3.80115 6.44151C3.93898 6.48685 4.06425 6.56392 4.16685 6.66653C4.26946 6.76913 4.34653 6.8944 4.39187 7.03223L5.27772 9.72547L6.16357 7.03223C6.20891 6.8944 6.28598 6.76913 6.38859 6.66653C6.49119 6.56392 6.61646 6.48685 6.7543 6.44151L9.44753 5.55566L6.7543 4.66981C6.61646 4.62447 6.49119 4.5474 6.38859 4.44479C6.28598 4.34219 6.20891 4.21692 6.16357 4.07909L5.27772 1.38585Z" fill="black" fill-opacity="0.15" stroke="black" stroke-width="1.2" stroke-linecap="round" stroke-linejoin="round"/>
-<path d="M8.35938 12.3555C8.35938 12.0664 8.52734 11.8086 9.00781 11.3594L10.2031 10.2344C10.6094 9.85156 10.7891 9.60156 10.7891 9.34375C10.7891 9.05469 10.5781 8.85938 10.2734 8.85938C10.0391 8.85938 9.87109 8.95312 9.66406 9.21094C9.42578 9.50781 9.25391 9.60938 8.99219 9.60938C8.61719 9.60938 8.35156 9.35938 8.35156 9.01172C8.35156 8.25 9.26953 7.57812 10.3594 7.57812C11.4961 7.57812 12.3438 8.26172 12.3438 9.17969C12.3438 9.75391 12.0391 10.3008 11.418 10.8516L10.4961 11.6719V11.7344H11.8047C12.2578 11.7344 12.5391 11.9766 12.5391 12.3711C12.5391 12.7656 12.2656 13 11.8047 13H9.08203C8.65234 13 8.35938 12.7383 8.35938 12.3555Z" fill="black"/>
-<path d="M11.0834 1.38585V3.71918M9.91675 2.55248H12.2501" stroke="black" stroke-opacity="0.75" stroke-width="1.25" stroke-linecap="round" stroke-linejoin="round"/>
-</svg>

crates/icons/src/icons.rs

@@ -231,7 +231,6 @@ pub enum IconName {
     X,
     XCircle,
     ZedAssistant,
-    ZedAssistant2,
     ZedAssistantFilled,
     ZedPredict,
     ZedPredictUp,