Possible duplicates in swagger.yml

When [looking through the swagger summaries](https://github.com/influxdata/influxdb/pull/19834), I noticed a few duplicates.

```
$ cd go/src/github.com/influxdata/influxdb/http/
$ cat swagger.yml | grep "summary:" | uniq -d
summary: Update a check
summary: Update a notification rule
summary: Update a notification endpoint
```

E.g., [here](https://github.com/influxdata/influxdb/blob/fab99c9512f86bd013fbd0c933865bbf17e9bfe7/http/swagger.yml#L5961) and [here](https://github.com/influxdata/influxdb/blob/fab99c9512f86bd013fbd0c933865bbf17e9bfe7/http/swagger.yml#L6000).

If these are in fact different, let's update the summaries. Otherwise some cleanup might be in order.