Don't disconnect gateway on any parsing error

[KrishnaIyer]

Summary

Don't disconnect gateway on any parsing error. Refs: https://github.com/TheThingsIndustries/lorawan-stack-support/issues/1082#issuecomment-2173098782

Changes

• Don't return an error when there are parsing errors. Instead just emit a warning and continue.

Testing

Local TTS.

Steps

1. Connect an LBS gateway (I'm using wscat to simulate).
2. Send an JSON message with an invalid MHdr.

   { "DR": 5, "Freq": 868100000, "upinfo": { "rctx": 0, "rxtime": 1718118631, "xtime": 5348025649894907, "gpstime": 1402153849237000, "rssi": -109, "snr": 1.8, "chan": 0 }, "msgtype": "updf", "MHdr": 155, "DevAddr": 843059200, "FCtrl": 22, "FCnt": 0, "FOpts": "1a0400009101", "FPort": -1, "FRMPayload": "", "MIC": 401, "RefTime": 1718118631.2550001 }

Results

Before:

• This would log a warning and disconnect.

After:

• This would still log the warning but the gateway is not disconnected.

Regressions

Don't expect any, This itself is a fix for a regression.

Checklist

• [x] Scope: The referenced issue is addressed, there are no unrelated changes.
• [x] 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.
• [x] 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.
• [x] Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.