PHPUnit 12: Fix RendererListTest - use createMock for LayoutInterface

Fixed fatal error: 'Class MockObject_LayoutInterface contains 32 abstract
methods'

LayoutInterface has 32 abstract methods. Using getMockBuilder()->onlyMethods()
with only 2 methods ['getBlock', 'getChildName'] causes a fatal error in
PHPUnit 12.

Solution: Replace with createMock(LayoutInterface::class) which automatically
handles all 32 interface methods. The methods we need (getBlock, getChildName)
can be configured on the mock created by createMock().

This is the same pattern as AdapterInterface (94 methods) and other large
interfaces: For interfaces with 30+ methods, ALWAYS use createMock() or
createStub(), never onlyMethods() with a partial list.

Author: manishranjan-adobe

lib/internal/Magento/Framework/View/Test/Unit/Element/RendererListTest.php

@@ -50,9 +50,8 @@ protected function setUp(): void
             ['setRenderedBlock', 'getTemplate', 'setTemplate']
         );
 
-        $this->layoutMock = $this->getMockBuilder(LayoutInterface::class)
-            ->onlyMethods(['getBlock', 'getChildName'])
-            ->getMock();
+        // LayoutInterface has 32 abstract methods - use createMock() instead of onlyMethods()
+        $this->layoutMock = $this->createMock(LayoutInterface::class);
 
         $this->layoutMock->expects($this->any())
             ->method('getBlock')