fix(webapp): add screen-reader text for the Test column cells

The Test cell on the Sessions table and the Test property on the session
detail page rendered an icon or dash with no text equivalent. Add an sr-only
Yes/No value and mark the check icon and dash aria-hidden.

Author: samejr

apps/webapp/app/components/sessions/v1/SessionsTable.tsx

@@ -147,10 +147,16 @@ export function SessionsTable({
                   </div>
                 </TableCell>
                 <TableCell to={sessionPath}>
+                  <span className="sr-only">{session.isTest ? "Yes" : "No"}</span>
                   {session.isTest ? (
-                    <CheckIcon className="size-4 text-charcoal-400 group-hover/table-row:text-text-bright" />
+                    <CheckIcon
+                      aria-hidden
+                      className="size-4 text-charcoal-400 group-hover/table-row:text-text-bright"
+                    />
                   ) : (
-                    "–"
+                    <span aria-hidden className="text-text-dimmed">
+                      –
+                    </span>
                   )}
                 </TableCell>
                 <TableCell to={sessionPath}>

apps/webapp/app/routes/_app.orgs.$organizationSlug.projects.$projectParam.env.$envParam.sessions.$sessionParam/route.tsx

@@ -821,10 +821,13 @@ function OverviewTab({ session, status }: { session: LoadedSession; status: Sess
         <Property.Item>
           <Property.Label>Test</Property.Label>
           <Property.Value>
+            <span className="sr-only">{session.isTest ? "Yes" : "No"}</span>
             {session.isTest ? (
-              <CheckIcon className="size-4 text-text-dimmed" />
+              <CheckIcon aria-hidden className="size-4 text-text-dimmed" />
             ) : (
-              <span className="text-text-dimmed">–</span>
+              <span aria-hidden className="text-text-dimmed">
+                –
+              </span>
             )}
           </Property.Value>
         </Property.Item>