remove unnecessarry test method

Author: dati18

tests/Helper/MWTimestampHelperTest.php

@@ -19,7 +19,6 @@ public function testGetCarbonFromMWTimestamp() {
 
     public function testGetCarbonFromMWTimestampWithInvalidTimestamp() {
         $this->expectException(InvalidFormatException::class);
-        $this->expectExceptionMessage('Unable to create Carbon object: invalid MW timestamp format');
 
         $invalidMwTimestamp = 'invalid_timestamp';
         MWTimestampHelper::getCarbonFromMWTimestamp($invalidMwTimestamp);