Update installation instructions in RL tutorials to use 'arbor-ai' package (#8200)

Author: isaacbmiller

docs/docs/tutorials/rl_multihop/index.ipynb

@@ -13,7 +13,7 @@
     "For this tutorial, you will also need DSPy's Arbor RL server.\n",
     "\n",
     "```bash\n",
-    "> pip install git+https://github.com/Ziems/arbor.git\n",
+    "> pip install arbor-ai\n",
     "> python -m arbor.cli serve --arbor-config arbor.yaml\n",
     "```\n",
     "\n",

docs/docs/tutorials/rl_papillon/index.ipynb

@@ -17,7 +17,7 @@
     "For this tutorial, you will also need the Arbor RL server.\n",
     "\n",
     "```bash\n",
-    "> pip install git+https://github.com/Ziems/arbor.git\n",
+    "> pip install arbor-ai\n",
     "> python -m arbor.cli serve --arbor-config arbor.yaml\n",
     "```\n",
     "\n",