vibrator: Add -f Shell Option

Add a command-line option -f to force vibration,
ignoring Do Not Disturb mode.

Bug: 123602968
Test: Sanity Check Via 'cmd vibrator'
Change-Id: I68be0c0e2d270290e3f139216ed143ecff9b6b57
Signed-off-by: Harpreet "Eli" Sangha <eliptus@google.com>