@W-15205338 adding new rule for unguarded async ops and eventing

[abhagta-sfdc]

@lpomerleau here is the log for lint scan in es-content-authoring repo with no-unguarded-async-event enabled [lint.log](https://github.com/user-attachments/files/17469921/lint.log)

[pmdartus]

Thanks for sharing the ESLint logs @abhagta-sfdc.

Looking at the results, in it's current shape the @lwc/lwc/ssr-no-unguarded-async-event rule creates too many false positive. Here are a couple of examples from the log containing 394 warnings:

• "Unguarded 'await' expression is not allowed during SSR." is emitted 4 times in emailUtils.ts. There is nothing incompatible with server-side rendering in this file.
• "Unguarded event operation 'dispatchEvent' is not allowed during SSR." is emitted twice in event.js. Same observation as above, there is nothing in this file that is indicating that those events are dispatched during server-side rendering.

I wouldn't recommend engineers to adopt this rule. Requiring to wrap all async code and event dispatching in import.meta.env.SSR checks will result in worse quality and less maintainable code. This is the type of issue, I expect to be addressed through comprehensive testing unit and integration testing, not through static analysis.

[abhagta-sfdc]

@pmdartus Thank you for the review! As per the description in the work item assigned to us, we were supposed to flag all async/await or event operations. Your clarification is helpful and much appreciated. @lpomerleau Just checking to confirm if we should close this PR(as PM's suggestion is to deal this via comprehensive testing unit and integration testing)

[pmdartus]

Please don't close the PR for now @abhagta-sfdc. This is my take on those rules, but I am not the decision maker here.

[lpomerleau]

I'm on board to close this PR. We have public and internal doc which discourages the use of async operations. Additionally, async code does not break SSR; it just doesn't get fully executed, so it is still technically portable.