Update icon dimensions to match source PNGs

Retaining base dimension of the icons removes artifacts caused when resizing to non-divisible sizes.

* circle button icons (search)
* Close "X"s
* Main menu icons

lib/ui/screens/artifact/artifact_carousel/artifact_carousel_screen.dart

@@ -128,7 +128,7 @@ class _ArtifactScreenState extends State<ArtifactCarouselScreen> {
           trailing: (context) => CircleBtn(
             semanticLabel: $strings.artifactsButtonBrowse,
             onPressed: _handleSearchTap,
-            child: AppIcon(AppIcons.search),
+            child: AppIcon(AppIcons.search, size: 24),
           ),
         ),
       ],

lib/ui/screens/artifact/artifact_search/time_range_selector/expanding_time_range_selector.dart

@@ -195,7 +195,7 @@ class _OpenedTimeRange extends StatelessWidget {
                 semanticLabel: $strings.expandingTimeSelectorSemanticSelector,
                 enableFeedback: false, // handled when panelController changes.
                 icon: AppIcons.close,
-                iconSize: 20,
+                iconSize: 24,
                 padding: EdgeInsets.symmetric(vertical: $styles.insets.xxs),
                 bgColor: Colors.transparent,
               ),

lib/ui/screens/artifact/artifact_search/widgets/_search_input.dart

@@ -154,8 +154,8 @@ class _SearchInput extends StatelessWidget {
                   color: $styles.colors.white,
                   icon: AppIcons.close,
                   semanticLabel: $strings.searchInputSemanticClear,
-                  size: $styles.insets.md,
-                  iconSize: $styles.insets.sm,
+                  size: $styles.insets.lg,
+                  iconSize: 24,
                   onPressed: () {
                     textController.clear();
                     onSubmit('');

lib/ui/screens/home_menu/home_menu.dart

@@ -205,7 +205,7 @@ class _MenuTextBtn extends StatelessWidget {
       child: Row(
         mainAxisAlignment: MainAxisAlignment.center,
         children: [
-          AppIcon(icon, color: $styles.colors.offWhite),
+          AppIcon(icon, color: $styles.colors.offWhite, size: 24),
           Gap($styles.insets.xs),
           Text(label, style: $styles.text.bodyBold.copyWith(height: 1)),
         ],