Remove oauth from tuning notebook (#311)

* Remove oauth from tuning notebook

* Add standard colab-secret-usage message

quickstarts/Tuning.ipynb

@@ -82,62 +82,53 @@
     {
       "cell_type": "markdown",
       "metadata": {
-        "id": "SWxKvwd-MSIV"
+        "id": "41fbd6a3290a"
       },
       "source": [
-        "## OAuth Authentication"
+        "## Setup"
       ]
     },
     {
-      "cell_type": "markdown",
+      "cell_type": "code",
+      "execution_count": null,
       "metadata": {
-        "id": "JjS8Zy1ojIgc"
+        "id": "cbcf72bcb56d"
       },
+      "outputs": [],
       "source": [
-        "Unlike the other quickstarts which use API keys, model tuning uses OAuth.\n",
-        "\n",
-        "This tutorial assumes you have completed the [OAuth Quickstart](https://github.com/google-gemini/cookbook/blob/main/quickstarts/Authentication_with_OAuth.ipynb) and you have your client secret saved as `CLIENT_SECRET` in the Colab secrets manager.\n",
-        "\n",
-        "> Important: **Don't just click the link this command prints**. That will fail. Follow the instructions and copy the `gcloud` command it prints to your local machine and run it there, then paste the output from your local machine back\n",
-        "here."
+        "!pip install -q -U \"google-generativeai>=0.7.2\""
       ]
     },
     {
       "cell_type": "code",
       "execution_count": null,
       "metadata": {
-        "id": "9FUwyB_MJ0-2"
+        "id": "8enrppafJPCX"
       },
       "outputs": [],
       "source": [
-        "from google.colab import userdata\n",
-        "import pathlib\n",
-        "pathlib.Path('client_secret.json').write_text(userdata.get('CLIENT_SECRET'))\n",
-        "\n",
-        "# Use `--no-browser` in colab\n",
-        "!gcloud auth application-default login --no-browser --client-id-file client_secret.json --scopes='https://www.googleapis.com/auth/cloud-platform,https://www.googleapis.com/auth/generative-language.tuning'"
+        "import google.generativeai as genai"
       ]
     },
     {
-      "cell_type": "code",
-      "execution_count": null,
+      "cell_type": "markdown",
       "metadata": {
-        "id": "cbcf72bcb56d"
+        "id": "41fbd6a3290a"
       },
-      "outputs": [],
       "source": [
-        "!pip install -q -U \"google-generativeai>=0.7.2\""
+        "To run the following cell, your API key must be stored it in a Colab Secret named `GOOGLE_API_KEY`. If you don't already have an API key, or you're not sure how to create a Colab Secret, see the [Authentication](https://github.com/google-gemini/cookbook/blob/main/quickstarts/Authentication.ipynb) quickstart for an example."
       ]
     },
     {
       "cell_type": "code",
       "execution_count": null,
       "metadata": {
-        "id": "8enrppafJPCX"
+        "id": "dc09b1db88b7"
       },
       "outputs": [],
       "source": [
-        "import google.generativeai as genai"
+        "from google.colab import userdata\n",
+        "genai.configure(api_key=userdata.get('GOOGLE_API_KEY'))"
       ]
     },
     {