When adding texts or various simple effects I often copy-paste strips
to reuse properties from a template such as font or position. I assume
this is common workflow. Issue with this workflow is, that active strip
is not changed after pasting, so when adjusting property, it is original
strip that is being modified.
This is not issue when duplicating strips - selection state is
transfered to duplicate strips, such that duplicate of active strip is
set to be active and duplicate of selected strip is set to selected.
Implement same selection transfering behavior in paste operator, that
exists in duplicate operator.
Since strip can be deleted after copying, it is not possible to rely
on sequencer state. This is true even when pasting strips to different
scene. Therefore active strip name must be stored in clipboard.
Reviewed By: sergey, Severin
Differential Revision: https://developer.blender.org/D11781
