libprocessgroup: Convert libprocessgroup_util to static library

To avoid duplicate symbol linker error and prep for addition of json
descriptor reading and activation functions in upcoming changes.

Bug: 349105928
Test: m
Change-Id: I5cd663d6007ef330b872b8cf8ed046ee68b6d736
diff --git a/libprocessgroup/util/Android.bp b/libprocessgroup/util/Android.bp
index 4a940b7..54ba69b 100644
--- a/libprocessgroup/util/Android.bp
+++ b/libprocessgroup/util/Android.bp
@@ -19,7 +19,7 @@
     default_applicable_licenses: ["Android-Apache-2.0"],
 }
 
-cc_library_headers {
+cc_library_static {
     name: "libprocessgroup_util",
     vendor_available: true,
     product_available: true,
@@ -36,12 +36,15 @@
     export_include_dirs: [
         "include",
     ],
+    srcs: [
+        "util.cpp",
+    ],
     defaults: ["libprocessgroup_build_flags_cc"],
 }
 
 cc_test {
     name: "libprocessgroup_util_test",
-    header_libs: ["libprocessgroup_util"],
+    static_libs: ["libprocessgroup_util"],
     srcs: ["tests/util.cpp"],
     test_suites: ["general-tests"],
 }