Fix: replace terminates extract mode (floating toolbar)

Moved the replace action to be triggered from the TextView
rather than the Editor. Previously the ExtractedEditText
was calling the TextView.onTextContextMenuItem which did
not hold an entry for replace and thus was returning
false.

Note: this CL does not fix the extracted mode being
(randomly) terminated when edit actions are pressed. This
is still under investigation.

Bug: 20930071
Change-Id: I71f87418f040f6860fe7723e4cd731c298cf3c5f