Add `aria-pressed` to vault and send list buttons

Programmatically denote which of the buttons is currently active/shown in the right-most panel

src/app/send/send.component.html

@@ -43,6 +43,7 @@
           title="{{ 'viewItem' | i18n }}"
           (contextmenu)="viewSendMenu(s)"
           [ngClass]="{ active: s.id === sendId }"
+          [attr.aria-pressed]="s.id === sendId"
           class="flex-list-item"
         >
           <span class="item-icon" aria-hidden="true">

src/app/vault/ciphers.component.html

@@ -14,6 +14,7 @@
         (contextmenu)="rightClickCipher(c)"
         title="{{ 'viewItem' | i18n }}"
         [ngClass]="{ active: c.id === activeCipherId }"
+        [attr.aria-pressed]="c.id === activeCipherId"
         class="flex-list-item virtual-scroll-item"
       >
         <app-vault-icon [cipher]="c"></app-vault-icon>