[server] Put text-input (de-)activate, en-/disable callbacks in child classes
Summary:
The activate/deactivate and enable/disable callback functionality was in the
TextInputInterface::Private interface, but these calls are each specific to v0
and v2 of the protocol.
Since v3 will have again a different function signature, put all the callbacks
and their helper functions in the protocol version specific child classes.
Test Plan: Compiles, runs.
Reviewers: KWin, Frameworks, davidedmundson, zzag
Reviewed By: KWin, davidedmundson, zzag
Subscribers: zzag, kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D16676