chore: Update AWS provider to 'ecr' for ECR authentication

[edgarsilva948]

Description

• Updated AWS provider configuration to use alias 'ecr' and hardcode the region to 'us-east-1' for ECR authentication in patterns that use public ECR images and require authentication.

Motivation and Context

• The intention is to keep the consistency in all repositories. This change ensures clear documentation and prevents users from mistakenly altering the region.

How was this change tested?

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• [] Yes, I have updated the docs for this feature
• [] Yes, I ran pre-commit run -a with this PR

Additional Notes

There is a provider here link with the old format, but it's not being used, so I didn't change it. Is it ok to update?