test/log: adopt newly revamped `setup()`

test/lib/log.bats

@@ -1,11 +1,10 @@
-#!/usr/bin/env bats
+# shellcheck shell=bats
 
-load ../test_helper
-load ../../lib/colors
+load "${MAIN_BASH_IT_DIR?}/test/test_helper.bash"
 
-load ../../lib/log
-load ../../lib/helpers
-load ../../plugins/available/base.plugin
+function local_setup_file() {
+  setup_libs "log"
+}
 
 @test "lib log: basic debug logging with BASH_IT_LOG_LEVEL_ALL" {
   BASH_IT_LOG_LEVEL=$BASH_IT_LOG_LEVEL_ALL