feat(ivy): introduce missing-injectable migration for google3 (#30956)

Introduces a new migration schematic for adding the "@Injectable()"
decorator to provider classes which are currently not migrated. Previously
in ViewEngine, classes which are declared as providers sometimes don't
require the "@Injectable()" decorator
(e.g. https://stackblitz.com/edit/angular-hpo7gw)

With Ivy, provider classes need to be explicitly decorated with
the "@Injectable()" decorator if they are declared as providers
of a given module. This commit introduces a migration schematic
which automatically adds the explicit decorator to places where
the decorator is currently missing.

The migration logic is designed in a CLI devkit and TSlint agnostic
way so that we can also have this migration run as part of a public
CLI migration w/ `ng update`. This will be handled as part of a follow-up to reiterate on console output etc.

Resolves FW-1371

PR Close #30956

packages/core/schematics/migrations/missing-injectable/BUILD.bazel

@@ -0,0 +1,21 @@
+load("//tools:defaults.bzl", "ts_library")
+
+ts_library(
+    name = "missing-injectable",
+    srcs = glob(["**/*.ts"]),
+    tsconfig = "//packages/core/schematics:tsconfig.json",
+    visibility = [
+        "//packages/core/schematics:__pkg__",
+        "//packages/core/schematics/migrations/missing-injectable/google3:__pkg__",
+        "//packages/core/schematics/test:__pkg__",
+    ],
+    deps = [
+        "//packages/compiler-cli/src/ngtsc/imports",
+        "//packages/compiler-cli/src/ngtsc/partial_evaluator",
+        "//packages/compiler-cli/src/ngtsc/reflection",
+        "//packages/core/schematics/utils",
+        "@npm//@angular-devkit/schematics",
+        "@npm//@types/node",
+        "@npm//typescript",
+    ],
+)