fix(ui): remove broken onfocusout handler from role edit dropdown

- onfocusout on the wrapper span was firing when focus moved to child buttons,
  cancelling the edit before the button onclick handlers ran
- Confirm/cancel now works via explicit button clicks only
- Starting a new edit on a different row implicitly cancels the previous one

Refs #45

MilkStream.Client/Components/Pages/AdminUsers.razor

@@ -98,7 +98,7 @@
                         <td>@user.Email</td>
                         <td>
                             @if (_editingAccessLevel == user.Id) {
-                                <span @onfocusout="CancelAccessLevelEdit" tabindex="0">
+                                <span>
                                     <select class="form-select form-select-sm" style="width:auto;display:inline"
                                             value="@((int)_pendingAccessLevel)"
                                             @onchange="(ChangeEventArgs e) => PendingAccessLevelChanged(e)">
@@ -107,11 +107,11 @@
                                         <option value="2">Admin</option>
                                     </select>
                                     <button class="btn btn-sm btn-success" title="Confirm"
-                                            @onclick="() => ConfirmAccessLevel(user)" @onfocusout:stopPropagation>
+                                            @onclick="() => ConfirmAccessLevel(user)">
                                         <i class="bi bi-check"></i>
                                     </button>
                                     <button class="btn btn-sm btn-outline-secondary" title="Cancel"
-                                            @onclick="CancelAccessLevelEdit" @onfocusout:stopPropagation>
+                                            @onclick="CancelAccessLevelEdit">
                                         <i class="bi bi-x"></i>
                                     </button>
                                 </span>