Add pixel for VPN menu item (#6908)

Task/Issue URL:
https://app.asana.com/1/137249556945/task/1211542874528796?focus=true

### Description
Add temporary pixel when VPN menu item is selected

### Steps to test this PR

_Pre-steps_
- [x] Apply PPro patch ->
https://app.asana.com/1/137249556945/project/1209991789468715/task/1210448620621729?focus=true
- [x] Set device language to English (United Kingdom)

_Not Subscribed_
- [x] Fresh install
- [x] Open a new tab page
- [x] VPN menu item will show with yellow pill "TRY FOR FREE"
- [x] Tap on VPN menu item
- [x] Check in Logcat pixel is sent: `Pixel sent:
m_nav_vpn_menu_item_pressed with params: {status=pill}`

_Not Subscribed & No Pill_
- [x] Open a new tab
- [x] Open overflow menu at least 3 more times
- [x] Open a new tab
- [x] Open overflow menu
- [x] VPN menu item doesn't have the yellow 'TRY FOR FREE' pill anymore
- [x] Tab on VPN item
- [x] Check in Logcat pixel is sent: `Pixel sent:
m_nav_vpn_menu_item_pressed with params: {status=no_pill}`

_Subscribed_
- [ ] Purchase a test subscription
- [ ] Go to browser and open a new tab
- [ ] Open overflow menu
- [ ] Tap on VPN menu item
- [ ] Check in Logcat pixel is sent: `Pixel sent:
m_nav_vpn_menu_item_pressed with params: {status=subscribed}`

### No UI changes

Author: nalcalag

app/src/androidTest/java/com/duckduckgo/app/browser/BrowserTabViewModelTest.kt

@@ -7928,4 +7928,46 @@ class BrowserTabViewModelTest {
 
         override fun getPlugins(): Collection<PostMessageWrapperPlugin> = listOf(plugin)
     }
+
+    @Test
+    fun whenVpnMenuClickedWithNotSubscribedStateThenPixelFiredWithPillStatus() {
+        testee.browserViewState.value = browserViewState().copy(
+            vpnMenuState = VpnMenuState.NotSubscribed,
+        )
+
+        testee.onVpnMenuClicked()
+
+        verify(mockPixel).fire(
+            AppPixelName.MENU_ACTION_VPN_PRESSED,
+            mapOf(PixelParameter.STATUS to "pill"),
+        )
+    }
+
+    @Test
+    fun whenVpnMenuClickedWithNotSubscribedNoPillStateThenPixelFiredWithNoPillStatus() {
+        testee.browserViewState.value = browserViewState().copy(
+            vpnMenuState = VpnMenuState.NotSubscribedNoPill,
+        )
+
+        testee.onVpnMenuClicked()
+
+        verify(mockPixel).fire(
+            AppPixelName.MENU_ACTION_VPN_PRESSED,
+            mapOf(PixelParameter.STATUS to "no_pill"),
+        )
+    }
+
+    @Test
+    fun whenVpnMenuClickedWithSubscribedStateThenPixelFiredWithSubscribedStatus() {
+        testee.browserViewState.value = browserViewState().copy(
+            vpnMenuState = VpnMenuState.Subscribed(isVpnEnabled = true),
+        )
+
+        testee.onVpnMenuClicked()
+
+        verify(mockPixel).fire(
+            AppPixelName.MENU_ACTION_VPN_PRESSED,
+            mapOf(PixelParameter.STATUS to "subscribed"),
+        )
+    }
 }

app/src/main/java/com/duckduckgo/app/browser/BrowserTabViewModel.kt

@@ -4469,18 +4469,22 @@ class BrowserTabViewModel @Inject constructor(
 
     fun onVpnMenuClicked() {
         val vpnMenuState = currentBrowserViewState().vpnMenuState
-        when (vpnMenuState) {
+        val statusParam = when (vpnMenuState) {
             VpnMenuState.NotSubscribed -> {
                 command.value = LaunchPrivacyPro("https://duckduckgo.com/pro?origin=funnel_appmenu_android".toUri())
+                "pill"
             }
             VpnMenuState.NotSubscribedNoPill -> {
                 command.value = LaunchPrivacyPro("https://duckduckgo.com/pro?origin=funnel_appmenu_android".toUri())
+                "no_pill"
             }
             is VpnMenuState.Subscribed -> {
                 command.value = LaunchVpnManagement
+                "subscribed"
             }
-            VpnMenuState.Hidden -> {} // Should not happen as menu item should not be visible
+            VpnMenuState.Hidden -> "" // Should not happen as menu item should not be visible
         }
+        pixel.fire(AppPixelName.MENU_ACTION_VPN_PRESSED, mapOf(PixelParameter.STATUS to statusParam))
     }
 
     fun onAutoConsentPopUpHandled(isCosmetic: Boolean) {

app/src/main/java/com/duckduckgo/app/pixels/AppPixelName.kt

@@ -263,6 +263,7 @@ enum class AppPixelName(override val pixelName: String) : Pixel.PixelName {
     MENU_ACTION_APP_LINKS_OPEN_PRESSED("m_nav_app_links_open_menu_item_pressed"),
     MENU_ACTION_DOWNLOADS_PRESSED("m_nav_downloads_menu_item_pressed"),
     MENU_ACTION_AUTOFILL_PRESSED("m_nav_autofill_menu_item_pressed"),
+    MENU_ACTION_VPN_PRESSED("m_nav_vpn_menu_item_pressed"),
 
     FIREPROOF_WEBSITE_ADDED("m_fw_a"),
     FIREPROOF_WEBSITE_REMOVE("m_fw_r"),

statistics/statistics-api/src/main/java/com/duckduckgo/app/statistics/pixels/Pixel.kt

@@ -71,6 +71,7 @@ interface Pixel {
         const val IS_TAB_SWITCHER_BUTTON_SHOWN = "is_tab_switcher_button_shown"
         const val IS_FIRE_BUTTON_SHOWN = "is_fire_button_shown"
         const val IS_BROWSER_MENU_BUTTON_SHOWN = "is_browser_menu_button_shown"
+        const val STATUS = "status"
     }
 
     object PixelValues {