remove leftover temp annotation from pre-null safe world (#20234)

Co-authored-by: NDavid Iglesias <ditman@gmail.com>

lib/ui/compositing.dart

@@ -699,12 +699,12 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   /// texture just before resizing the Android view and un-freezes it when it is
   /// certain that a frame with the new size is ready.
   void addTexture(
-    int/*!*/ textureId, {
-    Offset/*!*/ offset = Offset.zero,
-    double/*!*/ width = 0.0,
-    double/*!*/ height = 0.0,
-    bool/*!*/ freeze = false,
-    FilterQuality/*!*/ filterQuality = FilterQuality.low,
+    int textureId, {
+    Offset offset = Offset.zero,
+    double width = 0.0,
+    double height = 0.0,
+    bool freeze = false,
+    FilterQuality filterQuality = FilterQuality.low,
   }) {
     assert(offset != null, 'Offset argument was null'); // ignore: unnecessary_null_comparison
     _addTexture(offset.dx, offset.dy, width, height, textureId, freeze, filterQuality.index);

lib/ui/geometry.dart

@@ -656,7 +656,7 @@ class Rect {
   /// Constructs a rectangle from its center point, width, and height.
   ///
   /// The `center` argument is assumed to be an offset from the origin.
-  Rect.fromCenter({ required Offset center/*!*/, required double width, required double height }) : this.fromLTRB(
+  Rect.fromCenter({ required Offset center, required double width, required double height }) : this.fromLTRB(
     center.dx - width / 2,
     center.dy - height / 2,
     center.dx + width / 2,

lib/ui/painting.dart

@@ -3191,8 +3191,8 @@ class Gradient extends Shader {
     List<Color> colors, [
     List<double>? colorStops,
     TileMode tileMode = TileMode.clamp,
-    double startAngle/*?*/ = 0.0,
-    double endAngle/*!*/ = math.pi * 2,
+    double startAngle = 0.0,
+    double endAngle = math.pi * 2,
     Float64List? matrix4,
   ]) : assert(_offsetIsValid(center)),
        assert(colors != null), // ignore: unnecessary_null_comparison

lib/web_ui/lib/src/ui/painting.dart

@@ -1186,8 +1186,8 @@ abstract class Gradient extends Shader {
     List<Color> colors, [
     List<double>? colorStops,
     TileMode tileMode = TileMode.clamp,
-    double startAngle /*?*/ = 0.0,
-    double endAngle /*!*/ = math.pi * 2,
+    double startAngle = 0.0,
+    double endAngle = math.pi * 2,
     Float64List? matrix4,
   ]) =>
       engine.GradientSweep(center, colors, colorStops, tileMode, startAngle,