LP#1805895 Bucket grid configuration updates do not save

LP#1805895 Bucket grid configuration updates do not save

Some saved columns stick, but others are ignored. Issue affects eg-grid[s]
that use the auto-fields attr to load all columns on idl-class attr. This
is because saved columns are whitelisted against the initial column config
before the auto fields are loaded.

Patch adds $scope.handleAutoFields() to egCore.hatch.getItem. This happens
after the eg-grid-fields transclude (no collisions) but before the saved
columns are whitelisted. The original call remains to handle cases where
there is no persist-key or saved config.

Test:
1. Go to Circulation->User Buckets
2. Add the Is Deleted column to the grid
3. Save columns and refresh (note Is Deleted is not visible)
4. Apply patch and repeat steps 1-3 (note Is Deleted is now visible)

Signed-off-by: Dan Briem <dbriem@wlsmail.org>
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>