Update FlutterViewController.mm (#21362)

Tweaked the label here a little for style ("apps", not "application" -- plural and shorter); and "launching" rather than "re-launching"?
diff --git a/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm b/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
index 09773b0..7922560 100644
--- a/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
+++ b/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
@@ -343,9 +343,9 @@
     messageLabel.autoresizingMask =
         UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
     messageLabel.text =
-        @"In iOS 14+, Flutter application in debug mode can only be launched from Flutter tooling, "
+        @"In iOS 14+, debug mode Flutter apps can only be launched from Flutter tooling, "
         @"IDEs with Flutter plugins or from Xcode.\n\nAlternatively, build in profile or release "
-        @"modes to enable re-launching from the home screen.";
+        @"modes to enable launching from the home screen.";
     [placeholder addSubview:messageLabel];
   }