[fenix] Use consistent verbiage with regard to opened tabs (https://github.com/mozilla-mobile/fenix/pull/6550)

app/src/androidTest/java/org/mozilla/fenix/ui/robots/HomeScreenRobot.kt

@@ -203,7 +203,7 @@ private fun assertAddTabButton() =
         .check(matches(withEffectiveVisibility(Visibility.VISIBLE)))
 
 private fun assertNoTabsOpenedHeader() =
-    onView(CoreMatchers.allOf(ViewMatchers.withText("No tabs opened")))
+    onView(CoreMatchers.allOf(ViewMatchers.withText("No open tabs")))
         .check(matches(withEffectiveVisibility(Visibility.VISIBLE)))
 
 private fun assertNoTabsOpenedText() {

app/src/main/java/org/mozilla/fenix/home/sessioncontrol/SessionControlUIView.kt

@@ -20,7 +20,7 @@ import org.mozilla.fenix.mvi.UIView
 
 val noTabMessage = AdapterItem.NoContentMessage(
     R.drawable.ic_tabs,
-    R.string.no_open_tabs_header,
+    R.string.no_open_tabs_header_2,
     R.string.no_open_tabs_description
 )
 

app/src/main/res/values/strings.xml

@@ -15,7 +15,7 @@
     <!-- Placeholder text shown in the search bar before a user enters text -->
     <string name="search_hint">Search or enter address</string>
     <!-- No Open Tabs Message Header -->
-    <string name="no_open_tabs_header">No tabs opened</string>
+    <string name="no_open_tabs_header_2">No open tabs</string>
     <!-- No Open Tabs Message Description -->
     <string name="no_open_tabs_description">Your open tabs will be shown here.</string>