Remove striped tables in UI (#36509)

We've been cutting down on the "striped" tables (where rows are using
alternate row background colors). This completely removes them as I
think such a design looks outdated.

The removal of selectors starting with `.ui[class*="very
basic"].table:not(.striped)` is needed because of a specificity issue in
the CSS where table cells would otherwise render with incorrect padding.

Example of one affected table:

<img width="1027" height="224" alt="image"
src="https://github.com/user-attachments/assets/2f3006ca-99a1-4655-afdb-b7cd9e5f19c7"
/>

templates/admin/notice.tmpl

@@ -3,7 +3,7 @@
 		<h4 class="ui top attached header">
 			{{ctx.Locale.Tr "admin.notices.system_notice_list"}} ({{ctx.Locale.Tr "admin.total" .Total}})
 		</h4>
-		<table class="ui attached segment select selectable striped table unstackable g-table-auto-ellipsis">
+		<table class="ui attached segment select selectable table unstackable g-table-auto-ellipsis">
 			<thead>
 				<tr>
 					<th></th>