[IMP] web: make it possible to prefix KanbanAnimatedNumber

Use the `prefix` slot to give a prefix to KanbanAnimatedNumber, making
it possible to add text while not needing to extend the class/template.

Part-of: odoo/odoo#98837

addons/web/static/src/views/kanban/kanban_animated_number.js

@@ -45,5 +45,12 @@ KanbanAnimatedNumber.props = {
     animationClass: { type: String, optional: true },
     currency: { type: [Object, Boolean], optional: true },
     title: { type: String, optional: true },
+    slots: {
+        type: Object,
+        shape: {
+            prefix: { type: Object, optional: true },
+        },
+        optional: true,
+    },
 };
 KanbanAnimatedNumber.enableAnimations = true;

addons/web/static/src/views/kanban/kanban_animated_number.xml

@@ -3,6 +3,7 @@
 
     <t t-name="web.KanbanAnimatedNumber" owl="1">
         <div class="o_kanban_counter_side ms-2 text-900 text-nowrap" t-att-class="state.value !== props.value and props.animationClass" t-att-title="props.title">
+            <t t-slot="prefix"/>
             <span t-if="props.currency and props.currency.position === 'before'" t-esc="props.currency.symbol" class="ms-1"/>
             <b t-esc="format(state.value)" />
             <span t-if="props.currency and props.currency.position === 'after'" t-esc="props.currency.symbol" class="ms-1"/>