[Physical Keyboard] Update strings and descriptions

Update pointer speed preference to match with markup.
we already have pointer speed option under mouse setting page.

Bug: 405833943
Bug: 409173731
Bug: 364122861
Flag: EXEMPT bugfix
Test: atest
packages/apps/Settings/tests/robotests/src/com/android/settings/inputmethod/

Change-Id: I7aa3e2937bf9d1cd2895aac1c5067e7835ebc911