Update new string for One-Handed feature

According One-handed mode string review doc to change strings.

Bug: 151993111

Test: manual
Test: make RunSettingsRoboTests ROBOTEST_FILTER="com.android.settings
.gestures.OneHandedTimeoutPreferenceControllerTest"

Change-Id: I7dc961387c1e14b25438e051ce6b1cc70fb59417