[FIX] web: stop wrapping kanban counter over multiple lines

Note: this should normally not be the case by design as for most
values there is enough space for the numbers not to wrap. While
waiting for a better implementation, the white-space:nowrap CSS
rule will enforce the behavior.

Thank you to @Jerther for the original commit.

Closes https://github.com/odoo/odoo/pull/24100

addons/web/static/src/less/kanban_column_progressbar.less

@@ -91,6 +91,7 @@
         margin-left: 3%;
         color: @headings-color;
         text-align: right;
+        white-space: nowrap;
         .o-transform-origin(right, center);
 
         &.o_kanban_grow {