Add support for assume_role_with_web_identity to the S3 remote state block

[AndrewArmstrongVL]

Describe the enhancement

Add support for assume_role_with_web_identity to the S3 remote state block.

Implications of the feature

Direct support for this would be favourable over generating additional files or loosing the ability to automatically deploy underlying infrastructure. This will also maintain parity with underlying functionality of Terraform/OpenTOFU.
Several CI/CD tools (GitHub Action in our case) use OIDC to enable authentication with AWS, implementing this enhancement will allow for easier direct integrations with these tools.

Describe alternatives you've considered

• One workaround is to not use the terragrunt remote_state block and use a generate block and generate a terraform file for the backend configuration.
• Another workaround is to generate a ~/.aws/config file. and use the profile option.