rules_haskell_tests: Remove buildifier check, as it is deprecated

Use `//buildifier:buildifier_test` to check for proper formatting.

Author: avdv

rules_haskell_tests/buildifier/BUILD.bazel

@@ -1,14 +1,8 @@
 load("@com_github_bazelbuild_buildtools//buildifier:def.bzl", "buildifier", "buildifier_test")
 
-# Run this to check for errors in BUILD files.
-buildifier(
-    name = "buildifier",
-    mode = "check",
-)
-
 # Run this to fix the errors in BUILD files.
 buildifier(
-    name = "buildifier-fix",
+    name = "buildifier",
     mode = "fix",
     verbose = True,
 )