[FIX] mail: regarding scheduling activity in list view

Open a activity view(record modal), that will show records, clicking on the
'o_activity_btn' of a record will show dropdown and make sure that there are
many scheduled activity there .

Before this commit:

The dropdown was bigger than the record modal which had a scroll bar. It was not
scrollable properly and "+ Schedule Activity" button is not accessible.

After this commit:

The dropdown follows the scroll, and it will be possible to click the button.

Task- 2528111

closes odoo/odoo#87823

X-original-commit: 6436950bae7a8d0e3ec4a6eb83f42a3208a100d4
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/mail/static/src/xml/web_kanban_activity.xml

@@ -3,7 +3,7 @@
 
 <t t-name="mail.KanbanActivity">
     <div class="o_kanban_inline_block dropdown o_mail_activity">
-        <a class="dropdown-toggle o-no-caret o_activity_btn" data-toggle="dropdown" role="button">
+        <a class="dropdown-toggle o-no-caret o_activity_btn" data-boundary="viewport" data-flip="false" data-toggle="dropdown" role="button">
             <!-- span classes are generated dynamically (see _render) -->
             <span t-att-title="widget.selection[widget.activityState]" role="img" t-att-aria-label="widget.selection[widget.activity_state]"/>
        </a>