perf: add dynamically loaded cache-dependencies for actions python

This reduces the main bundle size by ⚠️  1.28 MB minified! This bundle is loaded only when caching is enabled.

`setup-python` is used in [`setup-cpp`](https://github.com/aminya/setup-cpp) as a library. This optimization reduces the bundle size for that package as well. The build system of `setup-python` uses `ncc`, which doesn't immediately benefit from this change, but setup-cpp uses `Parcel`, which shows this huge improvement.

The reason for this huge reduction is that caching the dependencies uses the `@actions/cache` package, which is an extremely large package with big dependencies. The bundle size before this separation shows this:
![Screenshot_20230907_230625](https://github.com/actions/setup-python/assets/16418197/ec1baf34-85c3-459d-b8cf-894899959b2c)

package.json

@@ -116,7 +116,7 @@
     "prettier-config-atomic": "^3.1.0",
     "retry-as-promised": "^7.0.4",
     "semver": "7.5.4",
-    "setup-python": "github:actions/setup-python#v4.7.0",
+    "setup-python": "github:aminya/setup-python#a783db655c6e40317e2c0c96f9d162d9c9f4a751",
     "shx": "0.3.4",
     "simple-update-notifier": "^2.0.0",
     "terser-config-atomic": "^1.0.0",

src/python/actions_python.ts

@@ -5,20 +5,13 @@ import { info, warning } from "ci-log"
 import { debug } from "@actions/core"
 import { join } from "patha"
 import { GITHUB_ACTIONS } from "ci-info"
-import { isCacheFeatureAvailable, IS_MAC } from "setup-python/src/utils"
-import { getCacheDistributor } from "setup-python/src/cache-distributions/cache-factory"
+import { IS_MAC } from "setup-python/src/utils"
 import { pathExists } from "path-exists"
 
 function isPyPyVersion(versionSpec: string) {
   return versionSpec.startsWith("pypy")
 }
 
-export async function cacheDependencies(cache: string, pythonVersion: string) {
-  const cacheDependencyPath = undefined
-  const cacheDistributor = getCacheDistributor(cache, pythonVersion, cacheDependencyPath)
-  await cacheDistributor.restoreCache()
-}
-
 const checkLatest = false
 
 export async function setupActionsPython(version: string, _setupDir: string, arch: string) {
@@ -45,9 +38,10 @@ export async function setupActionsPython(version: string, _setupDir: string, arc
       info(`Successfully set up ${installed.impl} (${pythonVersion})`)
     }
 
-    if (isCacheFeatureAvailable()) {
-      const cache = "pip" // package manager used for caching
-      await cacheDependencies(cache, pythonVersion)
+    const cache = true
+    if (cache) {
+      const { cacheDependencies } = await import("setup-python/src/cache-dependencies")
+      await cacheDependencies("pip", pythonVersion)
     }
   }