Recommend adding "Enable Model access" to the README instructions

[teharris1]

Describe the bug I believe this is a repeat of the issue #87, however, that issue was closed and does not appear to have been resolved.

When using the workshop for the first time on an account that has never used Bedrock before the error appears when invoking cell Amazon Titan Text Premier in the bedrock_basics.ipynb notebook:

You don't have access to the model with the specified model ID.                
To troubeshoot this issue please refer to the following resources.                 
https://docs.aws.amazon.com/IAM/latest/UserGuide/troubleshoot_access-denied.html                 
https://docs.aws.amazon.com/bedrock/latest/userguide/security-iam.html

To Reproduce Steps to reproduce the behavior (or some version of this):

1. Start in an account with no model access provided
2. Follow the Getting Started instructions
3. Test the setup using the bedrock_basics.ipynb notebook
4. See error in the output of the Amazon Titan Text Premier cell

Expected behavior The Getting Started section should reference the directions on how to enable model access such as: https://docs.aws.amazon.com/bedrock/latest/userguide/model-access.html#add-model-access

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: NA
• Browser N/A
• Version N/A

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

! Additional context !

• Visual Studio Code with Jupyter notebook
• SSO enabled on account
• AdministratorAccess role used
• Notebook cloned 8/15/2024