[FIX] project: correctly align buttons on project kanban

Previously, footer buttons on the project's kanban were not
being shown properly due to improper CSS rules.

This commit fixes the issue by removing fixed width and evenly
distributing available space between the buttons.

Task - 1948176

closes odoo/odoo#33039

Signed-off-by: Jérome Maes (jem) <jem@openerp.com>

addons/project/static/src/scss/project_dashboard.scss

@@ -1,25 +1,14 @@
 .o_kanban_view.o_kanban_dashboard.o_project_kanban {
     .o_project_kanban_boxes {
         display: flex;
-        flex-flow: row nowrap;
+        flex-flow: row wrap;
+        justify-content: space-between;
 
         .o_project_kanban_box {
             position: relative;
             text-align: center;
             padding: 0 0 0 0;
-            width: 33.33%;
-
-            &:last-child {
-                text-align: right;
-            }
-
-            &:nth-child(2){
-                width: 66.66%;
-            }
-
-            &:first-child {
-                text-align: left;
-            }
+            margin: 0 5px;
 
             .o_value {
                 font-weight: 800;
@@ -45,13 +34,6 @@
                 }
             }
         }
-        .o_project_timesheet_box{
-            position: relative;
-            padding: 0 0 0 0;
-            /* The important are here to assure this class is display in the center */
-            width: 33.33% !important;
-            text-align: center !important;
-        }
     }
 }