ts/BUILD.bazel: add missing import

Found by Buildifire presubmit:

  Function "sh_binary" is not global anymore and needs to be loaded from
  "@rules_shell//shell:sh_binary.bzl".

Signed-off-by: Marcin Radomski <dextero@google.com>

ts/BUILD.bazel

@@ -1,6 +1,7 @@
 load("@aspect_rules_js//npm:defs.bzl", "npm_package")
 load("@aspect_rules_ts//ts:defs.bzl", "ts_project")
 load("@flatbuffers_npm//:defs.bzl", "npm_link_all_packages")
+load("@rules_shell//shell:sh_binary.bzl", "sh_binary")
 
 filegroup(
     name = "distribution",