Bug 1845307 - Add missing testTag for synced tabs list composable

app/src/main/java/org/mozilla/fenix/tabstray/syncedtabs/SyncedTabs.kt

@@ -26,6 +26,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.toMutableStateList
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.tooling.preview.Preview
@@ -39,6 +40,7 @@ import org.mozilla.fenix.compose.button.PrimaryButton
 import org.mozilla.fenix.compose.ext.dashedBorder
 import org.mozilla.fenix.compose.list.ExpandableListHeader
 import org.mozilla.fenix.compose.list.FaviconListItem
+import org.mozilla.fenix.tabstray.TabsTrayTestTag
 import org.mozilla.fenix.theme.FirefoxTheme
 import mozilla.components.browser.storage.sync.Tab as SyncTab
 
@@ -64,7 +66,9 @@ fun SyncedTabsList(
         remember(syncedTabs) { syncedTabs.map { EXPANDED_BY_DEFAULT }.toMutableStateList() }
 
     LazyColumn(
-        modifier = Modifier.fillMaxSize(),
+        modifier = Modifier
+            .fillMaxSize()
+            .testTag(TabsTrayTestTag.syncedTabsList),
         state = listState,
     ) {
         if (taskContinuityEnabled) {