fix(docs): fix bugs and improve quality of LF notebook

- Use assumed role session for lf_client, glue_client, and
  athena_client instead of default boto3 session
- Move client initialization to setup/configuration cell
- Add session=boto_session to get_record in Example 2
- Fix print statements: "execution role" -> "offline store role"
- Remove unused get_execution_role import
- Remove misleading LakeFormationDataLakeAdmin comment
- Fix typo: "Exectution" -> "Execution"
- Fix PascalCase variables to snake_case
- Fix "lakeformation" -> "Lake Formation" in markdown
- Fix bold markdown formatting
- Add missing space in ARN print
- Remove duplicate boto3 and time imports
- Scope cleanup IAM policy to lf-demo-* resources
- Fix cleanup variable to use correct reference
- Remove empty trailing markdown cell

Author: BassemHalim

v3-examples/ml-ops-examples/v3-feature-store-examples/feature-store-lakeformation-cross-account.ipynb

@@ -119,7 +119,6 @@
     "    producer_account: f\"arn:aws:iam::{producer_account}:role/<role>\",\n",
     "    consumer_account: f\"arn:aws:iam::{consumer_account}:role/<role>\"\n",
     "}\n",
-    "\n",
     "central_acc_boto_session = assume_role(acc_to_role_arn[central_account])\n",
     "central_acc_sagemaker_session = SageMakerSession(boto_session=central_acc_boto_session)\n",
     "\n",
@@ -221,7 +220,7 @@
     "    enabled=True,\n",
     "    use_service_linked_role=False,\n",
     "    registration_role_arn=acc_to_role_arn[central_account],\n",
-    "    disable_hybrid_access_mode=True\n",
+    "    disable_hybrid_access_mode=False\n",
     ")\n",
     "\n",
     "# create FG in central account and enable LF\n",