Fix for case insensitive string comparison assertion in checkbox grou…

…p field test

In SilverStripe 4.4 field labels are sentence cased. This changes the assertion to be flexible
and pass in 4.4+ as well as <=4.3

tests/Forms/TextCheckboxGroupFieldTest.php

@@ -27,7 +27,8 @@ protected function setUp()
 
     public function testFieldIsAssignedFirstFieldsTitleInConstructor()
     {
-        $this->assertSame('Hello World', $this->field->Title());
+        // Note: SilverStripe 4.0-4.3 = "Hello World", 4.4+ "Hello world"
+        $this->assertTrue(strcasecmp('Hello World', $this->field->Title()) === 0);
     }
 
     public function testFieldReturnsCompositeFieldTemplateOnReadonlyTransformation()