Remove calling sequence of the PixelCablingCondAlg at initialization (ATLASRECTS-5710)

This reflects the fixes in the IDRegSelTools (!36883 (merged)), addressing the problem described in ATLASRECTS-4788.

The problem was SiRegionSelectorTable::createTable() was called at initialization step to fill the detector region, but at this level (initialization), the ConditionHandle does not fill the DB contents, thus, PixelCabling information is missing if the DB contents are not filled at initialization.

Therefore, at those time, the ad-hoc solution was to call the filling scheme at PixelCablingCondAlg::initialization(). But this leads the incorrect setting between initialization() and execute().

Now, the Region selector moves into conditions, and no more call of SiRegionSelectorTable::createTable(), the PixelCablingAlg also don't need to fill the DB contents at initialization.