fix: only assign CellRangeSelector when Hybrid has dragToSelect set

[ghiscoding]

partially reverts PR #1164 and commit 43e31fa

I previously added a row-click as selection type in the new Hybrid Selection, because I taught that I needed it since it behave differently when comparing Row Selection and the new Hybrid Selection (e.g. Master/Detail grids example). But in reality, the real problem was simply a missing condition in which we should only instantiate SlickCellRangeDecorator as selector when undefined and when dragToSelect is enabled and that was the missing piece in the new Hybrid Model. After adding the missing condition, the Hybrid Selection Model is now behaving the same as the Row Selection Model and/or Cell Selection Model.

Note: I discovered this issue while working on dropping SlickCellSelectionModel & SlickRowSelectionModel in Slickgrid-Universal to replace them entirely with a single SlickHybridSelectionModel that handles both type of selections