Fix gateway server event data change during marshaling

[vlasebian]

Summary

References support issue #1163.

Changes

• Clone event data when registering evtGatewayConnectionStats
• Add panic recover with logging in event data marshalling function

Testing

TODO

Steps

Results

Regressions

None.

Notes for Reviewers

I'm not really sure if this will give us more info than the debug stack that's already shown on panic recovery of the task.

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Testing: The steps/process to test this feature are clearly explained including testing for regressions.
• Infrastructure: If infrastructural changes (e.g., new RPC, configuration) are needed, a separate issue is created in the infrastructural repositories.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.