healthd: add healthd.rc

Split healthd section from init.rc into its own. This allows
healthd.rc to be excluded from the build when healthd is excluded.

Test: builds
Test: exclude healthd from build, healthd.rc is not installed
Bug: 77541952
Change-Id: I1c055f14c5862631f359fd0029289da8f43af063
diff --git a/healthd/Android.bp b/healthd/Android.bp
index c70278a..a28544e 100644
--- a/healthd/Android.bp
+++ b/healthd/Android.bp
@@ -56,6 +56,7 @@
 
 cc_binary {
     name: "healthd",
+    init_rc: ["healthd.rc"],
     srcs: [
         "HealthServiceHealthd.cpp",
     ],