chore: wait longer for plans to appear
chore: wait longer for plans to appear

this is a system-tests-fix. it might take a while till an SDK is deployed and
shows the contents of its plan-tab. let's give it a little more time to spin up,
which seems a reasonable thing to do in real environments. at least for my
CCM-clusters i'm consistently able to reproduce that message although a couple
seconds later the correct information is delivered.

dcos/dcos-ui,dcos/dcos-ui,dcos/dcos-ui,dcos/dcos-ui,dcos/dcos-ui