feat: Add Eraser 🎉 (#4887)

* feat: Add Eraser 🎉

* Eraser working

* remove unused state

* fix

* toggle eraser

* Support deselect with Alt/Option

* rename actionDelete -> actionErase

* Add util isEraserActive

* show eraser in mobile

* render eraser conditionally in mobile

* use selection if eraser in local storage state

* Add sampling to erase accurately

* use pointerDownState

* set eraser to false in AllowedExcalidrawElementTypes

* rename/reword fixes

* don't use updateScene

* handle bound text when erasing

* fix hover state in mobile

* consider all hitElements instead of a single

* code improvements

* revert to select if eraser active and elements selected

* show eraser in zenmode

* erase element when clicked on element while eraser active

* set groupIds to empty when eraser active

* fix test

* remove dragged distance

src/css/styles.scss

@@ -290,6 +290,16 @@
     width: 100%;
 
     box-sizing: border-box;
+
+    .eraser {
+      &.ToolIcon:hover {
+        --icon-fill-color: #fff;
+        --keybinding-color: #fff;
+      }
+      &.active {
+        background-color: var(--color-primary);
+      }
+    }
   }
 
   .App-toolbar-content {
@@ -467,7 +477,8 @@
     font-family: var(--ui-font);
   }
 
-  .undo-redo-buttons {
+  .undo-redo-buttons,
+  .eraser-buttons {
     display: grid;
     grid-auto-flow: column;
     gap: 0.4em;