refactor(core): remove disabled injectable-pipe migration (#32184)

Initially the plan was to have a migration that adds `@Injectable()` to
all pipes in a CLI project so that the pipes can be injected in Ivy
similarly to how it worked in view engine.

Due to the planned refactorings which ensure that `@Directive`, `@Component`
and `@Pipe` also have a factory definition, this migration is no longer
needed for Ivy. Additionally since it is already disabled (due to
572b54967c) and we have a more generic
migration (known as `missing-injectable)` that could do the same as
`injectable-pipe`, we remove the migration from the code-base.

PR Close #32184

packages/core/schematics/BUILD.bazel

@@ -10,7 +10,6 @@ npm_package(
     srcs = ["migrations.json"],
     visibility = ["//packages/core:__pkg__"],
     deps = [
-        "//packages/core/schematics/migrations/injectable-pipe",
         "//packages/core/schematics/migrations/move-document",
         "//packages/core/schematics/migrations/renderer-to-renderer2",
         "//packages/core/schematics/migrations/static-queries",