Update notification in submission_list_view

[classPythonAddike]

When submissions have not opened, and someone clicks on the View Submissions button on the timathon page, it shows an alert on the top right hand corner saying that voting hasn't started yet. I changed it to Submissions haven't closed yet :mhmf:

[SylteA]

Hey @classPythonAddike

Will you complete this PR?

[classPythonAddike]

Sure :mhm:

[Shubhaankar-Sharma]

Hey @classPythonAddike Please keep it clean, we want to branch from Tech-With-Tim:dev since there are already commits on that branc, after that we can merge it to master at once

[classPythonAddike]

ok