Uniques: Reset approved account after transfer (#12145)

* reset approved account

* wrap at 100

* doc

* fmt

* Update frame/uniques/src/tests.rs

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* new test

* Update frame/uniques/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* fmt

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>