Improve the Gradient tool by visualizing color stops (#3698)

* Gradient

* improvement

* removed unnecessary code

* corrected error

* Partical changes

* Improveded

* remove from advertised actions

* Mousedown

* Partial code review

* changes as per recommendation

* corrected error

* corrected error -2

* changes as per recommendation

* error corrected

* changes as suggested

* Bug Fix

* Fix hints

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

editor/src/test_utils.rs

@@ -210,6 +210,18 @@ impl EditorTestUtils {
 		.await;
 	}
 
+	pub async fn left_mouseup(&mut self, x: f64, y: f64, modifier_keys: ModifierKeys) {
+		self.mouseup(
+			EditorMouseState {
+				editor_position: (x, y).into(),
+				mouse_keys: MouseKeys::empty(),
+				scroll_delta: ScrollDelta::default(),
+			},
+			modifier_keys,
+		)
+		.await;
+	}
+
 	pub async fn input(&mut self, message: InputPreprocessorMessage) {
 		self.handle_message(Message::InputPreprocessor(message)).await;
 	}