[FIX] im_livechat: adapt window height

Since PR[1] the size of the chatWindow has been increased in the
backend.
But on the frontend, this window has kept the old height.

This commit fixes this issue.

PR[1] : https://github.com/odoo/odoo/pull/92872

closes odoo/odoo#101508

X-original-commit: bd9849361d2a72ddd9a036edcf31fab21316d909
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/im_livechat/static/src/legacy/public_livechat.scss

@@ -11,7 +11,7 @@ $o-mail-thread-window-zindex: $zindex-modal + 1 !default;
     position: fixed;
     width: $o-mail-thread-window-width;
     max-width: 100%;
-    height: 400px;
+    height: 460px;
     max-height: 100%;
     font-size: 12px;
     background-color: $o-mail-thread-window-bg;