luci-theme-bootstrap: fix textarea height after CSS minification

Fixes #2378
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

themes/luci-theme-bootstrap/htdocs/luci-static/bootstrap/cascade.css

@@ -550,7 +550,7 @@ select[multiple] {
 }
 
 textarea {
-	height: auto;
+	height: auto !important;
 }
 
 .td > input[type=text],