Fixed block group extra attribute sorting issue

[hbugdoll]

What are you changing/introducing

• Make block groups' extra attribute groupLabel non-sortable

What is the reason for changing/introducing

• Sorting by Group (groupLabel) in Groups Management table raises a SQL error:

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'groupLabel' in 'order clause'
The SQL being executed was: SELECT * FROM `cms_block_group` WHERE `cms_block_group`.`is_deleted`=FALSE ORDER BY `groupLabel` LIMIT 25

QA

Q	A
Is bugfix?	yes
New feature?	no
Breaks BC?	no
Tests pass?	yes
Fixed issues	–