Replace FullScreenLoadingIndicator with ActivityIndicator in WorkspacesListPage

As part of the loading indicator standardization (Expensify#69850), replace
FullScreenLoadingIndicator with a plain ActivityIndicator wrapped in a View
with fullScreenLoading styles in WorkspacesListPage.tsx. This prevents the
upcoming shouldUseGoBackButton default from showing duplicate back controls
when TopBar and NavigationTabBar are already visible.

Co-authored-by: Situ Chandra Shil <situchan@users.noreply.github.com>

Author: MelvinBot

src/pages/workspace/WorkspacesListPage.tsx

@@ -8,7 +8,7 @@ import ConfirmModal from '@components/ConfirmModal';
 import type {DomainItem} from '@components/Domain/DomainMenuItem';
 import DomainMenuItem from '@components/Domain/DomainMenuItem';
 import DomainsEmptyStateComponent from '@components/DomainsEmptyStateComponent';
-import FullScreenLoadingIndicator from '@components/FullscreenLoadingIndicator';
+import ActivityIndicator from '@components/ActivityIndicator';
 import type {MenuItemProps} from '@components/MenuItem';
 import NavigationTabBar from '@components/Navigation/NavigationTabBar';
 import NAVIGATION_TABS from '@components/Navigation/NavigationTabBar/NAVIGATION_TABS';
@@ -738,9 +738,9 @@ function WorkspacesListPage() {
                 </TopBarWithLoadingBar>
                 {shouldUseNarrowLayout && <View style={[styles.ph5, styles.pt2]}>{headerButton}</View>}
                 {shouldShowLoadingIndicator ? (
-                    <View style={[styles.flex1]}>
-                        <FullScreenLoadingIndicator
-                            style={[styles.flex1, styles.pRelative]}
+                    <View style={[styles.flex1, styles.fullScreenLoading]}>
+                        <ActivityIndicator
+                            size={CONST.ACTIVITY_INDICATOR_SIZE.LARGE}
                             reasonAttributes={
                                 {
                                     context: 'WorkspacesListPage',