Update SDK details in release plan by automation on spec merge

Release plan automation pipeline creates or identifies a release plan whenever a spec PR is merged. It should add a new step post identifying an existing release plan to run update SDK details using TypeSpec project to update the package names from TypeSpec project.

Pipeline link: https://github.com/Azure/azure-rest-api-specs/blob/main/eng/pipelines/release-plan.yml

azsdk CLI command is to run:
azsdk release-plan update --typespec-path --output "json"

Note: azsdk release-plan update CLI command requires a change to avoid updating SDK release type and make it optional before this change is completed.

Start with eng/pipelines/release-plan.yml and trace how the pipeline identifies an existing release plan after a spec PR merge. Review the azsdk release-plan update command and its requirement that SDK release type be optional. Done means the post-identification step updates package names from the TypeSpec project and produces JSON output without changing release type.

Written by the indexing model from the issue text.