refactor: simplify bazel saucelabs targets using karma pre-test wrapper and shared saucelabs connection between tests (#34769)

* Added a /tools/saucelabs/sauce-service.sh script that manages the sauce-connect as a service which is used by the karma-saucelabs.js wrapper to start the service.
* Added /tools/saucelabs/README.md that covers the details of SauceLabs karma testing with Bazel.

PR Close #34769

tools/saucelabs/BUILD.bazel

@@ -0,0 +1,50 @@
+load("@build_bazel_rules_nodejs//:index.bzl", "nodejs_binary")
+
+package(default_visibility = ["//visibility:public"])
+
+sh_binary(
+    name = "sauce_service_setup",
+    srcs = ["sauce-service.sh"],
+    args = ["setup"],
+    data = ["@npm//sauce-connect"],
+)
+
+sh_binary(
+    name = "sauce_service_start",
+    srcs = ["sauce-service.sh"],
+    args = ["start"],
+    data = ["@npm//sauce-connect"],
+)
+
+sh_binary(
+    name = "sauce_service_start_ready_wait",
+    srcs = ["sauce-service.sh"],
+    args = ["start-ready-wait"],
+    data = ["@npm//sauce-connect"],
+)
+
+sh_binary(
+    name = "sauce_service_ready_wait",
+    srcs = ["sauce-service.sh"],
+    args = ["ready-wait"],
+    data = ["@npm//sauce-connect"],
+)
+
+sh_binary(
+    name = "sauce_service_stop",
+    srcs = ["sauce-service.sh"],
+    args = ["stop"],
+    data = ["@npm//sauce-connect"],
+)
+
+nodejs_binary(
+    name = "karma-saucelabs",
+    data = [
+        "sauce-service.sh",
+        "@npm//karma",
+        "@npm//sauce-connect",
+        "@npm//shelljs",
+    ],
+    entry_point = "karma-saucelabs.js",
+    templated_args = ["$(location sauce-service.sh)"],
+)