Migration mode is now the default

- Reflect production.
- Update SkinVector migration notes.

Depends-On: Ia527e60901de59f9e094ca0f1ba62a67a2f808a2
Change-Id: I8efa56fa0644b2ceb33fdab16da5df1d44ee621f

skin.json

@@ -403,7 +403,7 @@
 			"description": "@var string:['2'|'1'] The version ('2' for latest, '1' for legacy) of the Vector skin to **set** for newly created user accounts. **The value is persisted as a user preference.** This configuration is not used for preexisting accounts (see VectorDefaultSkinVersionForExistingAccounts) and only ever executed once at new account creation time."
 		},
 		"VectorSkinMigrationMode": {
-			"value": false,
+			"value": true,
 			"description": "@internal. For usage to fulfil [[phab:T291098]]"
 		},
 		"VectorWvuiSearchOptions": {

tests/phpunit/integration/VectorHooksTest.php

@@ -309,6 +309,12 @@ class VectorHooksTest extends MediaWikiIntegrationTestCase {
 	public function testOnGetPreferencesShowPreferencesEnabledSkinSectionFoundLegacy() {
 		$isLegacy = true;
 		$this->setFeatureLatestSkinVersionIsEnabled( !$isLegacy );
+		$config = new HashConfig( [
+			'VectorSkinMigrationMode' => false,
+			'VectorShowSkinPreferences' => true,
+			'VectorDefaultSidebarVisibleForAuthorisedUser' => true,
+		] );
+		$this->setService( 'Vector.Config', $config );
 
 		$prefs = [
 			'foo' => [],
@@ -375,6 +381,12 @@ class VectorHooksTest extends MediaWikiIntegrationTestCase {
 	public function testOnGetPreferencesShowPreferencesEnabledSkinSectionMissingLegacy() {
 		$isLegacy = false;
 		$this->setFeatureLatestSkinVersionIsEnabled( !$isLegacy );
+		$config = new HashConfig( [
+			'VectorSkinMigrationMode' => false,
+			'VectorDefaultSidebarVisibleForAuthorisedUser' => true,
+			'VectorShowSkinPreferences' => true,
+		] );
+		$this->setService( 'Vector.Config', $config );
 
 		$prefs = [
 			'foo' => [],