[TEST] Add test coverage for RegisterReceiveOperations.js in Core python websocket Template

[batchu5]

The RegisterReceiveOperations.js component contains conditional logic, but currently has no test coverage.

Adding tests would help ensure:

• The component returns null when receiveOperations is undefined or an empty array
• The generated output correctly serializes and renders discriminators

[Harsh16gupta]

@batchu5 This issue is part of the larger discussion in #1846 , please also have a look at PR #1866.
As per maintainer guidance, we decided to introduce a separate shared fixture for all baked-in templates. I’m currently developing this fixture step by step while adding component tests incrementally.
The plan is to first complete component tests for the Java template using the new fixture. Once that is stabilized, we can move on to the next templates and add tests for components like RegisterReceiveOperations.js using the same approach.
@Adi-204 what do you think?

[Adi-204]

@Harsh16gupta you are write but we don't need to block other issues. We now already have new fixture in main branch so others can also use it and add things if they want to in this case I think we need to add a receive operation. @batchu5 feel free to create PR but please use fixture https://github.com/asyncapi/generator/blob/master/packages/templates/clients/websocket/test/__fixtures__/asyncapi-websocket-components.yml for testing