[FIX] project: add space between caret and assignees dropdown

step to produce :
- go to project
- click on any project in the Kanban view
- click on the quick create button
- notice caret at assignees dropdown

issue:
- at the assignees dropdown the caret position is at the far right and not
  aligned with the discard/trash button

Cause:
- changes which happened in task-2944742 added left margin for user_ids field ,
  which then moved the position of caret.

Solution:
- changed css to just apply the margin at bottom right for M2M avatar at kanban
  and stopped it from affecting user_ids field in quick create task.

task-3506482

closes odoo/odoo#144987

X-original-commit: 519df29285700a33a515d640777745ca6a90fbab
Signed-off-by: Xavier Bol (xbo) <xbo@odoo.com>

addons/project/static/src/views/project_task_kanban/project_task_kanban_view.scss

@@ -1,5 +1,5 @@
 .o_kanban_project_tasks .o_kanban_renderer {
-    div.o_field_many2many_avatar_user[name="user_ids"] {
+    .oe_kanban_bottom_right > div.o_field_many2many_avatar_user[name="user_ids"] {
         margin-left: 6px;
     }