Add NOTICE file path to apex bundle base rule.

The NOTICE files are missing from prebuilt apexes, and it turns out they
were excluded when building bundles.

Bug: 140317706
Test: Ran build_mainline_modules.sh and checked bundle base modules.
Change-Id: I92c4231f2007e1d8cd9c2bd044201458803c0fd7

apex/apex.go

@@ -86,7 +86,8 @@ var (
 		Command: `${zip2zip} -i $in -o $out ` +
 			`apex_payload.img:apex/${abi}.img ` +
 			`apex_manifest.json:root/apex_manifest.json ` +
-			`AndroidManifest.xml:manifest/AndroidManifest.xml`,
+			`AndroidManifest.xml:manifest/AndroidManifest.xml ` +
+			`assets/NOTICE.html.gz:assets/NOTICE.html.gz`,
 		CommandDeps: []string{"${zip2zip}"},
 		Description: "app bundle",
 	}, "abi")