Add info on each WebView package in webviewupdate-dumpsys.

Add information such as versionName and versionCode for each WebView
package to the dumpState of WebViewUpdateService. Also print the package
that would be used at the time of printing if the package-choice logic
had been rerun then.

Bug: 35862676
Test: Ensure running 'adb shell dumpsys webviewupdate' prints correct
info.
Change-Id: Ic1eb576f4f58680a867c591c705cfcebf1d9a5b0