healthd: move healthd_board_init call to Health::Health() c-tor

The invocation is wrapped so that clients of -impl doesn't
have to call healthd_board_init directly.

Test: health VTS test
Test: charger_test
Bug: 69268160

Change-Id: I61f820b80ce6b03fe51ca05d07ed7e09ca369d2d
diff --git a/healthd/Health.cpp b/healthd/Health.cpp
index d271811..822f664 100644
--- a/healthd/Health.cpp
+++ b/healthd/Health.cpp
@@ -16,6 +16,8 @@
 sp<Health> Health::instance_;
 
 Health::Health(struct healthd_config* c) {
+    // TODO(b/69268160): remove when libhealthd is removed.
+    healthd_board_init(c);
     battery_monitor_ = std::make_unique<BatteryMonitor>();
     battery_monitor_->init(c);
 }