Remove duplicate check

Author: mpociot

config/config.php

@@ -11,9 +11,8 @@
         \BeyondCode\SelfDiagnosis\Checks\PhpExtensionsAreInstalled::class,
         \BeyondCode\SelfDiagnosis\Checks\EnvFileExists::class,
         \BeyondCode\SelfDiagnosis\Checks\ExampleEnvironmentVariablesAreSet::class,
-        \BeyondCode\SelfDiagnosis\Checks\EnvFileExists::class,
         \BeyondCode\SelfDiagnosis\Checks\DirectoriesHaveCorrectPermissions::class,
         \BeyondCode\SelfDiagnosis\Checks\StorageDirectoryIsLinked::class,
 	]
 
-];
+];