[FIX] web: daterangepicker, fix months arrows color

Before this commit, the arrows in the daterange picker to switch months
wasn't correctly displayed in light mode.
This visual bug was introduced due to styling changes made for
the dark-mode.

This commit fixes this.

closes odoo/odoo#104151

X-original-commit: caa5604fbf99f6cba763109e7c26fed6e2042642
Signed-off-by: Samuel Degueldre <sad@odoo.com>

addons/web/static/src/legacy/scss/daterangepicker.scss

@@ -40,7 +40,7 @@
         background-color: var(--daterangepicker__table-bg);
 
         .next span, .prev span {
-            border-color: currentColor;
+            border-color: var(--daterangepicker-color);
         }
 
         td, th {