Support showing battery level chart first immediately after the battery level data is ready.

When the battery level chart is shown but app usage data is not ready,
the battery chart is still clickable, but the app list won't show. Once
the app usage data is ready, the app usage list of the latest selected
period will show. Please see the following screen record of forcing
loading app usage data very slow. In the real case, the app usage
loading is not that slow.

https://drive.google.com/file/d/196rlzwSa52xrQFRfF2gdHJJPZn-uecZF/view?usp=sharing&resourcekey=0-mGggQGG7IMd5-bSAG7l_LA

Bug: 243887839
Fix: 243887839
Test: manual
Change-Id: I170eb4afb46b1d0040b7971460b1b37dde5d1362