Use the SkinMustache template variable for the main page link

Bug: T248752
Depends-On:  I98fc4755e6a736efc2210f8b6ddf4a1cc4eea378
Change-Id: I077abba357e503c79901b64be2ccbb3f2efe1c18

includes/SkinVector.php

@@ -115,7 +115,6 @@ class SkinVector extends SkinMustache {
 		//   It should be followed by the name of the hook in hyphenated lowercase.
 		//
 		// Conditionally used values must use null to indicate absence (not false or '').
-		$mainPageHref = Skin::makeMainPageUrl();
 
 		$parentData = parent::getTemplateData();
 
@@ -131,8 +130,6 @@ class SkinVector extends SkinMustache {
 
 			'input-location' => $this->getSearchBoxInputLocation(),
 
-			'main-page-href' => $mainPageHref,
-
 			'data-sidebar' => $this->getTemplateDataSidebar(),
 			'sidebar-visible' => $this->isSidebarVisible(),
 		], $this->getMenuProps() );

includes/templates/Logo.mustache

@@ -1,10 +1,10 @@
 {{!
 	LogoDefinition logo
-	string main-page-href link to the main page
+	string link-mainpage link to the main page (from SkinMustache in core)
 	string msg-sitesubtitle the contents of the sitesubtitle message key
 }}
 {{#data-logos}}
-<a href="{{main-page-href}}" class="mw-logo">
+<a href="{{link-mainpage}}" class="mw-logo">
 	{{#icon}}
 	{{! alt is provided for valid HTML but given aria-hidden not needed. }}
 	<img class="mw-logo-icon" src="{{.}}" alt=""