Support -f option for Current shell command

We've had historically added "-f" as a valid shell command option for
the battery service dumpsys get commands. However, with the current
state of the code, using -f with "get" results in an error.

In an attempt to both fix this error, and to support up-to-date
current-value fetching, we're
[1] Supporting the inclusion of -f option in "get" commands
[2] When -f is used, we schedule update with the health service before
fetching the current value, to help get the latest current value

Bug: 315037695
Test: adb shell dumpsys battery get -f current_now
Change-Id: I8ef1c420005d505b36869b6cea4de095a47e4993