Tweak Camera2D editor line colors for better visibility

The new color for screen drawing was chosen to be easier to distinguish
from the 2D viewport limits.

This also makes lines less opaque when the Camera2D has the Current
property enabled. The increased line width is enough to spot the
camera easily, and the increased opacity on top of that felt obnoxious.

scene/2d/camera_2d.cpp

@@ -270,11 +270,10 @@ void Camera2D::_notification(int p_what) {
 			}
 
 			if (screen_drawing_enabled) {
-				Color area_axis_color(0.5, 0.42, 0.87, 0.63);
+				Color area_axis_color(1, 0.4, 1, 0.63);
 				real_t area_axis_width = 1;
 				if (is_current()) {
 					area_axis_width = 3;
-					area_axis_color.a = 0.83;
 				}
 
 				Transform2D inv_camera_transform = get_camera_transform().affine_inverse();
@@ -295,10 +294,9 @@ void Camera2D::_notification(int p_what) {
 			}
 
 			if (limit_drawing_enabled) {
-				Color limit_drawing_color(1, 1, 0, 0.63);
+				Color limit_drawing_color(1, 1, 0.25, 0.63);
 				real_t limit_drawing_width = 1;
 				if (is_current()) {
-					limit_drawing_color.a = 0.83;
 					limit_drawing_width = 3;
 				}
 
@@ -317,11 +315,10 @@ void Camera2D::_notification(int p_what) {
 			}
 
 			if (margin_drawing_enabled) {
-				Color margin_drawing_color(0, 1, 1, 0.63);
+				Color margin_drawing_color(0.25, 1, 1, 0.63);
 				real_t margin_drawing_width = 1;
 				if (is_current()) {
 					margin_drawing_width = 3;
-					margin_drawing_color.a = 0.83;
 				}
 
 				Transform2D inv_camera_transform = get_camera_transform().affine_inverse();