libui: Add std::hash support for Rects/Region

Adds support for std::hash to Rect, FloatRect, and Region.

Bug: 158790260
Test: libui unit tests
Change-Id: I593bad1d3111d9b28984de5c2d80695c124e30b6
diff --git a/libs/ui/Android.bp b/libs/ui/Android.bp
index 714ee3e..a8d4762 100644
--- a/libs/ui/Android.bp
+++ b/libs/ui/Android.bp
@@ -220,9 +220,11 @@
     },
     header_libs: [
         "libnativewindow_headers",
+        "libmath_headers",
     ],
     export_header_lib_headers: [
         "libnativewindow_headers",
+        "libmath_headers",
     ],
     min_sdk_version: "29",
 }