Fix exception during github issue id reading

[ArtyomSavchenko]

Fix errors from github service logs:

{"err":{"message":"Cannot read properties of undefined (reading 'id')","stack":"TypeError: Cannot read properties of undefined (reading 'id')\n    at /usr/src/app/bundle.js:295678:58\n    at Array.map (<anonymous>)\n    at IssueSyncManager.externalSync (/usr/src/app/bundle.js:295678:34)\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)"},"level":"error","message":"Error","timestamp":"2026-02-11T13:58:29.069Z"}
{"action":"synchronize","level":"info","login":"tofijak","message":"pull request:handleEvent","nodeId":"https://github.com/Serpier/serpier/pull/718","timestamp":"2026-02-11T13:58:29.415Z","type":"User","workspace":"1f909283-5af7-4b56-b948-3d3cc141c9fb"}
{"action":"synchronize","id":"bda77610-0751-11f1-9d87-e9a5874f73d5","level":"info","message":"webhook event","name":"pull_request","timestamp":"2026-02-11T13:58:29.415Z"}
{"docs":14,"field":"externalVersion","level":"info","message":"External Syncing","name":"maxint-web","prj":"web","timestamp":"2026-02-11T13:58:29.550Z","version":"v4","workspace":"612a9d74-ad04-4a74-81d2-188e88cb351e"}
{"err":{"message":"Cannot read properties of undefined (reading 'id')","stack":"TypeError: Cannot read properties of undefined (reading 'id')\n    at /usr/src/app/bundle.js:295678:58\n    at Array.map (<anonymous>)\n    at IssueSyncManager.externalSync (/usr/src/app/bundle.js:295678:34)\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)"},"level":"error","message":"Error","timestamp":"2026-02-11T13:58:29.551Z"}
{"docs":14,"field":"externalVersion","level":"info","message":"External Syncing","name":"maxint-web","prj":"web","timestamp":"2026-02-11T13:58:29.915Z","version":"v4","workspace":"612a9d74-ad04-4a74-81d2-188e88cb351e"}
{"err":{"message":"Cannot read properties of undefined (reading 'id')","stack":"TypeError: Cannot read properties of undefined (reading 'id')\n    at /usr/src/app/bundle.js:295678:58\n    at Array.map (<anonymous>)\n    at IssueSyncManager.externalSync (/usr/src/app/bundle.js:295678:34)\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)"},"level":"error","message":"Error","timestamp":"2026-02-11T13:58:29.915Z"}

[huly-github-staging]

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