default theme: remove unused elm/uiclock
Summary:
Legacy widget is elm/clock, and the new one is efl/uiclock.
There does not exist a legacy elm/uiclock.
This also reverts commit
20404d79d43876c546ba8e969f6cb9ea38122772
(elm_datetime, efl_ui_clock : Add check 'legacy widget' for layout signal emission)
Since there is no need to check for legacy versions of uiclock.
Ref T6965
Reviewers: devilhorns, zmike
Reviewed By: zmike
Subscribers: cedric, #committers, zmike
Tags: #efl
Maniphest Tasks: T6965
Differential Revision: https://phab.enlightenment.org/D6450