Add IS_GENERATED_GESTURE to MotionFlags in input.rs

Because IS_GENERATED_GESTURE is actually used in touchpad gestures, it
is a legitimate flag. We should add it to MotionFlags; otherwise,
MotionFlags::from_bits will return a None, which is not the result we
want.

Bug: 335391081

Test: Enable inbound event verification and use two finger swipe on
touchpad, device it should not crash.

Signed-off-by: Linnan Li <lilinnan@xiaomi.corp-partner.google.com>
(cherry picked from https://partner-android-review.googlesource.com/q/commit:fc358ec0877fd60e15645fe2683fa5ad5067a8eb)
Merged-In: I9c1a3f52508c106837bcabef0e10c71f69d1dadf
Change-Id: I9c1a3f52508c106837bcabef0e10c71f69d1dadf
diff --git a/libs/input/rust/input.rs b/libs/input/rust/input.rs
index 705c959..f55e3c0 100644
--- a/libs/input/rust/input.rs
+++ b/libs/input/rust/input.rs
@@ -194,6 +194,8 @@
                 input_bindgen::AMOTION_EVENT_FLAG_IS_ACCESSIBILITY_EVENT;
         /// FLAG_NO_FOCUS_CHANGE
         const NO_FOCUS_CHANGE = input_bindgen::AMOTION_EVENT_FLAG_NO_FOCUS_CHANGE;
+        /// FLAG_IS_GENERATED_GESTURE
+        const IS_GENERATED_GESTURE = input_bindgen::AMOTION_EVENT_FLAG_IS_GENERATED_GESTURE;
     }
 }