Update the namespace for the compute bounds flag.

Previously I created a new namespace based on the filegroup name that
was already defined in the Android.bp. The namespace core_graphics is
already managed and this flag should just join our managed flags
already. This will be better than managing a new namespace just for this
flag.

Bug: 304478551
Test: make
Change-Id: Id116fa94da627a9687992d23cd31820cccf15c6a
diff --git a/graphics/java/android/framework_graphics.aconfig b/graphics/java/android/framework_graphics.aconfig
index e030dad..9a0a22a 100644
--- a/graphics/java/android/framework_graphics.aconfig
+++ b/graphics/java/android/framework_graphics.aconfig
@@ -2,7 +2,7 @@
 
 flag {
      name: "exact_compute_bounds"
-     namespace: "framework_graphics"
+     namespace: "core_graphics"
      description: "Add a function without unused exact param for computeBounds."
      bug: "304478551"
 }
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