fix(entries-table): increase skeleton rows from 10 to 15

Extend the loading state placeholder rows in the leaderboard entries 
table from 10 to 15 to better match anticipated data length and improve 
user experience during data fetch.

Author: rohitpaulk

app/components/leaderboard-page/entries-table.hbs

@@ -7,7 +7,7 @@
         </thead>
         <tbody>
           {{#if @isLoadingEntries}}
-            {{#each (range 1 11) as |rank|}}
+            {{#each (range 1 16) as |rank|}}
               <LeaderboardPage::EntriesTable::SkeletonRow @rankText={{concat "#" rank}} />
             {{/each}}
           {{else}}