fix(aalborg_theme): only pass body_attrs if they are set

Follow-up of #6479
fix(UserPicker): no messages in userpicker due to lack of i18n

default elgg autocomplete disabled the messages in jquery autocomplete,
this now also applies to the UserPicker
chore(release): v1.9.0-rc.1
Merge pull request #6860 from beck24/release-1.9.0-rc.1

chore(release): v1.9.0-rc.1
fix(deprecated): Corrected invalid deprecation notice and added more details to few others

Fixes #6869
Merge pull request #6848 from PerJensen/aalborg_update_pageshell

fix(aalborg_theme): only pass body_attrs if they are set
Merge pull request #6870 from Srokap/ticket_6869

fix(deprecated): Corrected invalid deprecation notice and added more details to few others
Merge pull request #6861 from jdalsem/UserPicker-i18n

fix(UserPicker): no messages in userpicker due to lack of i18n
Merge translations