checking for the ability to merge automatically broke

I had a stack of two PRs and i managed to get the first PR closed and tried to rebase the stack. I got this:

x-github-request-id: D183:D8B6E:27991D:364B7D:6A591DD1

```json
{
"state": "UNKNOWN",
"channels": {
"stateChannel": "eyJjIjoiaXNzdWU6NDg5NjIwMDUxMjpzdGF0ZSIsInQiOjE3ODQyMjUyMzN9--e4ae28e21e625aca8871908842f8520fbbd75aa64469510d00542498cd7c94ff",
"deployedChannel": "eyJjIjoicHVsbF9yZXF1ZXN0OjQwNjM2MDY3NjI6ZGVwbG95ZWQiLCJ0IjoxNzg0MjI1MjMzfQ==--22226205d2969cd11420e654205e2c588db43df1abccdee0640ab94867650ee7",
"reviewStateChannel": "eyJjIjoicHVsbF9yZXF1ZXN0OjQwNjM2MDY3NjI6cmV2aWV3X3N0YXRlIiwidCI6MTc4NDIyNTIzM30=--6bc7326e494154238fa723ac9917986a79fad7da1417344a651b613263c4fd0a",
"workflowsChannel": "eyJjIjoicHVsbF9yZXF1ZXN0OjQwNjM2MDY3NjI6d29ya2Zsb3dfcnVuIiwidCI6MTc4NDIyNTIzM30=--f144b40788e76d198b357fbbf4b33152738bd4cdedd841419f2d89a8bb14a0b8",
"codeScanningChannel": "eyJjIjoicHVsbF9yZXF1ZXN0OjQwNjM2MDY3NjI6Y29kZV9zY2FubmluZyIsInQiOjE3ODQyMjUyMzN9--6b1336644d79b6a24969cd771f0e4e736ad47a049a864ecb8bb40245e1da5e4a",
"mergeQueueChannel": "eyJjIjoicHVsbF9yZXF1ZXN0OjQwNjM2MDY3NjI6bWVyZ2VfcXVldWVfZW50cnlfc3RhdGUiLCJ0IjoxNzg0MjI1MjMzfQ==--f0e7d6f1cfa94bcc99670d37348ef5b9977e87f32eb7a8996806e46019f44fcd",
"headRefChannel": "eyJjIjoicmVwbzoxMzAyMDIzNDg3OmJyYW5jaDpqc29yZWYtcGF0Y2gtMiIsInQiOjE3ODQyMjUyMzN9--5de202b90fac8d6b85204ee7f567a8688d69ea1d8de2c0b9e8f314ba8e66ee65",
"baseRefChannel": "eyJjIjoicmVwbzoxMzAyMDIzNDg3OmJyYW5jaDpqc29yZWYtcGF0Y2gtMSIsInQiOjE3ODQyMjUyMzN9--c87562f3873f27c5bc77ab9969e158ad588171987323dfb0ff95c4477c7f2031",
"gitMergeStateChannel": "eyJjIjoicHVsbF9yZXF1ZXN0OjQwNjM2MDY3NjI6Z2l0X21lcmdlX3N0YXRlIiwidCI6MTc4NDIyNTIzM30=--4eb253765555a7448cfeb61b9fcc29e982363866d4709d5bb0d68426b18703b0",
"pullRequestChannel": "eyJjIjoicHVsbF9yZXF1ZXN0OjQwNjM2MDY3NjIiLCJ0IjoxNzg0MjI1MjMzfQ==--09dde74b381b1afc30cd7fa42cb9410f3ee04b30f81db536b21166f66fff516b"
},
"statusCheckChannels": {
"commitHeadShaChannel": "eyJjIjoicmVwbzoxMzAyMDIzNDg3OmNvbW1pdDpjY2I3NDc2NzY4NzkxYjU0ZDdiZTg0YjMyNDEzNGY1OTZhNzAwNTgyIiwidCI6MTc4NDIyNTIzM30=--7368aa09f2c20b801546d00da4d3323153c6f275de4300500b09ed35493ea381"
},
"effectiveEntryStatus": "LOADING"
}
```

No source file or test is named. Start by reproducing the stacked-PR rebase after closing the first pull request, then trace the check for automatic merge ability and its handling of the reported UNKNOWN and LOADING states. Done means the rebase reports the mergeability state correctly instead of remaining stuck in this response.

Written by the indexing model from the issue text.