Add aria label to search box on meetings detail page (#1337)

-   Ticket: [https://openscience.atlassian.net/browse/ENG-3214]
-   Feature flag: n/a

## Purpose

Add an aria label to the search box on the meetings detail page. Apparently last time I got the meeting list page, but not the detail page's search box.

## Summary of Changes

1. Add aria label

## Side Effects

No

## QA Notes

Just needs a11y testing.

Author: brianjgeiger

app/meetings/detail/-components/meeting-submissions-list/template.hbs

@@ -4,6 +4,7 @@
             @type='text'
             @placeholder={{t 'meetings.index.meetings-list.search'}}
             @key-up={{perform this.searchSubmissions}}
+            aria-label={{t 'meetings.index.meetings-list.search'}}
         />
     </div>
 </div>