[K6.3] Stripping linebreaks when removing attachment. (#9764)

* Update upload.main.js

Stripping linebreaks when removing attachment.

* Update upload.main.js

* Update upload.main.js

Removed Insert private attachment as this doesn't work. Inserted private attachments are still visible for everyone.
Buttons are now ok.

* Update upload.main.js

Remove all working I think

* Update upload.main.js

buttons display fixed and remove individual attachment now possible

* Update upload.main.js

Added buttons Is Private and all attachments private
Requires adding language constants COM_KUNENA_ATTACHMENT_IS_PRIVATE and COM_KUNENA_ALL_ATTACHMENTS_ARE_PRIVATE added to transifex

* Update upload.main.js

hide insert when private is clicked and hide private when insert is clicked for individual attachment and all attachments

* Update upload.main.js

changed language constants to existing language constants for private buttons

* Update upload.main.js

All buttons should now be hidden as expected.

* Update upload.main.js

* Update upload.main.js