feat: notifications sa-251 teams and sa-228 enrichmenbt

[wozzer72]

Utilising V1.0.1 of notifications to benefit from enriched Slack messaging.

Includes removing defunct slack channel and username and passing through of accounts id to name mapping.

NOTE - teams-budgets is not going to work: slack_notification does not exist on "budgets" variable. This is existing behaviour.

Have also taken the opportunity to replace the direct dependency on terraform-aws-modules/notify-slack in teams-budget module with the appvia notifications module.

[github-actions]

Pull Request Review Status

• 🖌 Terraform Format and Style: success
• 🔍 Terraform Linting: success
• 👮 Terraform Security Check: success
• 🔘 Terraform Tests: success
• 🔧 Terraform Initialisation: success
• 🤖 Terraform Validation: success
• 🤖 Terraform Example Validation: success
• 📖 Terraform Documentation: success
• 🔖 Commitlint: success

Working Directory: modules/team-budgets
Pusher: @wozzer72, Action: pull_request
Workflow Run Link: https://github.com/appvia/terraform-aws-budgets/actions/runs/10808316963

[github-actions]

Pull Request Review Status

• 🖌 Terraform Format and Style: success
• 🔍 Terraform Linting: success
• 👮 Terraform Security Check: success
• 🔘 Terraform Tests: success
• 🔧 Terraform Initialisation: success
• 🤖 Terraform Validation: success
• 🤖 Terraform Example Validation: success
• 📖 Terraform Documentation: success
• 🔖 Commitlint: success

Working Directory: modules/budgets
Pusher: @wozzer72, Action: pull_request
Workflow Run Link: https://github.com/appvia/terraform-aws-budgets/actions/runs/10808316963

[gambol99]

LGTM