[FIX] mail: thread content with few content should be at bottom

closes odoo/odoo#125163

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/mail/static/src/core/common/thread.xml

@@ -3,7 +3,7 @@
 
 <t t-name="mail.Thread" owl="1">
     <t t-if="env.inChatter" t-call="mail.Thread.jumpPresent"/> <!-- chatter has its own scrollable, this ensures proper sticky showing -->
-    <div class="o-mail-Thread position-relative flex-grow-1" t-att-class="{ 'overflow-auto': props.hasScrollAdjust, 'pb-4': !state.showJumpPresent }" t-ref="messages">
+    <div class="o-mail-Thread position-relative flex-grow-1 d-flex flex-column" t-att-class="{ 'overflow-auto': props.hasScrollAdjust, 'pb-4': !state.showJumpPresent }" t-ref="messages">
         <t t-if="!props.thread.isEmpty or props.thread.loadOlder or props.thread.hasLoadingFailed" name="content">
             <div class="d-flex flex-column position-relative flex-grow-1" t-att-class="{'justify-content-end': !env.inChatter and props.thread.type !== 'mailbox'}">
                 <span class="position-absolute w-100 invisible" t-att-class="props.order === 'asc' ? 'bottom-0' : 'top-0'" t-ref="present-treshold" t-att-style="`height: Min(${PRESENT_THRESHOLD}px, 100%)`"/>