Change dropdown hover color to white (#5593)
Change dropdown hover color to white (#5593)

Signed-off-by: Navaneesh Kumar <2e613f6bbe889f10946fd6e1abb3426640ec0d87@gmail.com>
keegancsmith/prometheus,alileza/prometheus,prometheus/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,alileza/prometheus,prometheus/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,keegancsmith/prometheus,kangwoo/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,prometheus/prometheus,alileza/prometheus,alileza/prometheus,kangwoo/prometheus