Update name of ANGLE Android apk to match expectations

Android build system wants to see pre-built components
like this with naming that indicates what it is.

Bug: angleproject:2702
Change-Id: I84acee78a6ceef5b04c87436c68d41510f6e66c7
Reviewed-on: https://chromium-review.googlesource.com/1155004
Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>

BUILD.gn

@@ -941,7 +941,7 @@ if (is_android) {
     # supported on M or later releases (which is true for Vulkan).
     # Allows tool to optimize for that.
     requires_sdk_api_level_23 = true
-    apk_name = "AngleLibraries"
+    apk_name = "ANGLEPrebuilt"
     uncompress_shared_libraries = true
     shared_libraries = [
       "//third_party/angle:libEGL${angle_libs_suffix}",