Enforce build file formatting in shaders with buildifier

Bug: b/532697459

Author: Databean

base/cvd/cuttlefish/host/graphics_detector/shaders/BUILD.bazel

@@ -1,9 +1,11 @@
-load("//cuttlefish/bazel:rules.bzl", "cf_cc_binary", "cf_cc_library")
+load("//cuttlefish/bazel:rules.bzl", "cf_build_test", "cf_cc_binary", "cf_cc_library")
 
 package(
     default_visibility = ["//:android_cuttlefish"],
 )
 
+cf_build_test(name = "cf_build_test")
+
 cf_cc_binary(
     name = "generate_shader_embed",
     srcs = ["generate_shader_embed.cpp"],