By this commit user can upload attachments by drag and drop in chatter composer.
This feature can be used from discuss UI, chat windows and form view chatter.
Before this commit chatter unlinks the attachment if another attachment uploaded
with same name. Criteria for removing duplicate attachment is changed with this
commit. Now it will remove the attachment based on name and size of attachment.
The reason for this change is, when you upload image with same name from different
directory with old condition it was not possible to attach more then one image/file
of same name.
Related to task #32469Closes#18914
Dharmang Soni
fb051d3420