[Resolver]: Check entire body for macro invocation

[malhotra5]

What problem or use case are you trying to solve?

Allow triggering the resolver if the macro trigger is present anywhere in the comment body.

Currently this would start resolver

@openhands-agent please fix this"

We also want to support such cases

"please fix this @openhands-agent"

Describe the UX of the solution you'd like N/A Do you have thoughts on the technical implementation? Edit .github/workflows/openhands-resolver.yml and openhands/resolver/examples/openhands-resolver.yml; replace the startsWith command with an alternative that checks across the entire comment body

Describe alternatives you've considered

Additional context