Final code for dotnet sample app deployment

[Jeel-mehta]

Issue description:

Description of changes: I have dynamically deployed the sample app for both the versions of dotnet support (8.0 and 6.0). I am attaching a link of github workflow where I have tested my code for version 6.0 and 8.0 for the region us-east-1. This specific code change will include and handle both versions for all the regions.

Rollback procedure:

<Can we safely revert this commit if needed? If not, detail what must be done to safely revert and why it is needed.>

Ensure you've run the following tests on your changes and include the link below:

To do so, create a test.yml file with name: Test and workflow description to test your changes, then remove the file for your PR. Link your test run in your PR description. This process is a short term solution while we work on creating a staging environment for testing.

NOTE: TESTS RUNNING ON A SINGLE EKS CLUSTER CANNOT BE RUN IN PARALLEL. See the needs keyword to run tests in succession.

• Run Java EKS on e2e-playground in us-east-1 and eu-central-2
• Run Python EKS on e2e-playground in us-east-1 and eu-central-2
• Run metric limiter on EKS cluster e2e-playground in us-east-1 and eu-central-2
• Run EC2 tests in all regions
• Run K8s on a separate K8s cluster (check IAD test account for master node endpoints; these will change as we create and destroy clusters for OS patching)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[majanjua-amzn]

Instead of looking for the default version '8.0' and replacing it, you should change wherever it says 8.0 to {{DOTNET_VERSION}} and use sed commands to replace all of the occurrences of that string