fix(cli): handle empty AsyncAPI file gracefully

[sahillllllllll-bit]

Description

• Adds an explicit validation check for empty AsyncAPI files in the generate fromTemplate command.
• Prevents the CLI from crashing with a raw JavaScript TypeError when the AsyncAPI document is empty.
• Returns an existing, user-friendly ValidationError (invalid-file) instead.

Related issue(s)

Fixes #1993

before

TypeError: Cannot read properties of undefined (reading 'asyncapi')

After

Error: Invalid AsyncAPI file provided: empty.yaml

[changeset-bot]

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Latest commit: 32b7262

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[AayushSaini101]

/u

[AayushSaini101]

@sahillllllllll-bit thank you for the contribution can please fix the test build : )

[sahillllllllll-bit]

@sahillllllllll-bit thank you for the contribution can please fix the test build : )

Thank you for the review! 😊
I’m fixing the test build now and will push the updated changes shortly.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[sahillllllllll-bit]

@sahillllllllll-bit thank you for the contribution can please fix the test build : )

Thanks! All checks are now passing. Please let me know if anything else is needed