[@azure/eventgrid-system-events]Initial Commit V1.0.0-beta.1

[sarangan12]

Packages impacted by this PR

@azure/eventgrid-system-events

Issues associated with this PR

NA

Describe the problem that is addressed by this PR

1. Originally, there was one unified package - @azure/eventgrid. This package was generated from Swagger specification.
2. Earlier in April 2024, some parts of the @azure/eventgrid package were extracted out to create a new package - @azure/eventgrid-namespaces. This package was generated from Typespec specification.
3. Now, with this PR, we are looking at the second split of the @azure/eventgrid package. All System Events have been extracted out of the swagger specification to Typespec specification. This is a new package named @azure/eventgrid-system-events.

What are the possible designs available to address the problem? If there are more than one possible design, why was the one in this PR chosen?

1. In the Typespec core generator, We have an issue where client name overrides are not applied to alias. I have created an issue [Bug]: Client Name Overrides are failing if the property is inherited(alias) from parent microsoft/typespec#3240 to fix this. In the meantime, I have handled this issue in the custom code.
2. With the new generator, Known* models are not generated. I have created an issue Known* definitions mission in TS Generation autorest.typescript#2476 to fix this. In the meantime, I have handled this issue in the custom code.
3. In the previous generator, we had several properties which were overridden as mandatory parameters. With the new generator, such mass overrides are not possible. So, we are allowing them to be optional and close to the Wore specification. This is in parity with the other language SDKs.

Are there test cases added in this PR? (If not, why?)

No. They are all model objects. No code functionality is involved.

Provide a list of related PRs (if any)

1. [Bug]: Client Name Overrides are failing if the property is inherited(alias) from parent microsoft/typespec#3240
2. Known* definitions mission in TS Generation autorest.typescript#2476
3. [@azure/eventgrid-namespaces] - Release EG Namespaces SDK V1.0.0-beta.1 #29245

Command used to generate this PR:**(Applicable only to SDK release request PRs)

npx tsp compile client.tsp

Checklists

• Added impacted package name to the issue description
• Does this PR needs any fixes in the SDK Generator?** (If so, create an Issue in the Autorest/typescript repository and link it here)
• Added a changelog (if necessary)

@xirzec @joheredi @lmazuel FYI......