Fixed the height of the dashboard designer container to provide more space to access the lower grid resize button.
Fixed the height of the dashboard designer container to provide more space to access the lower grid resize button.

(JIRA: https://wso2.org/jira/browse/UES-735)

lalankea/carbon-dashboards,keizer619/carbon-dashboards,lalankea/carbon-dashboards,keizer619/carbon-dashboards,keizer619/carbon-dashboards,lalankea/carbon-dashboards