Be explicit about test runner device

Given the default of `ios_xctestrun_runner`:

https://github.com/bazelbuild/rules_apple/blob/c5a3307c481c8fb5f9d8eefe53a62e1902b80410/apple/testing/default_runner/ios_xctestrun_runner.bzl#L55-L56
Signed-off-by: Matt Robinson <mattrob@hey.com>

modules/API/BUILD.bazel

@@ -1,6 +1,6 @@
 load("@build_bazel_rules_apple//apple:ios.bzl", "ios_unit_test")
 load("@build_bazel_rules_swift//swift:swift.bzl", "swift_library")
-load("//tools:shared.bzl", "default_test_runner", "versions")
+load("//tools:shared.bzl", "versions")
 
 # Code
 
@@ -33,7 +33,7 @@ swift_library(
 ios_unit_test(
     name = "APITests",
     minimum_os_version = versions.minimum_ios_version,
-    runner = default_test_runner,
+    runner = "//tools:default_test_runner",
     visibility = ["//modules:default_test_visibility"],
     deps = [":APITestsLib"],
 )

modules/Models/BUILD.bazel

@@ -1,6 +1,6 @@
 load("@build_bazel_rules_apple//apple:ios.bzl", "ios_unit_test")
 load("@build_bazel_rules_swift//swift:swift.bzl", "swift_library")
-load("//tools:shared.bzl", "default_test_runner", "versions")
+load("//tools:shared.bzl", "versions")
 
 # Code
 
@@ -30,7 +30,7 @@ swift_library(
 ios_unit_test(
     name = "ModelsTests",
     minimum_os_version = versions.minimum_ios_version,
-    runner = default_test_runner,
+    runner = "//tools:default_test_runner",
     visibility = ["//modules:default_test_visibility"],
     deps = [":ModelsTestsLib"],
 )

tools/BUILD.bazel

@@ -0,0 +1,11 @@
+load(
+    "@build_bazel_rules_apple//apple/testing/default_runner:ios_xctestrun_runner.bzl",
+    "ios_xctestrun_runner",
+)
+
+ios_xctestrun_runner(
+    name = "default_test_runner",
+    device_type = "iPhone 14",
+    random = True,
+    visibility = ["//visibility:public"],
+)

tools/shared.bzl

@@ -7,5 +7,3 @@ app_info = struct(
 versions = struct(
     minimum_ios_version = "18.0",
 )
-
-default_test_runner = Label("@build_bazel_rules_apple//apple/testing/default_runner:ios_xctestrun_random_runner")