CLI should retry 'Connection reset by peer' errors returned from the cloud on GET requests

CLI version: 3.2.0-dev (`157e024b545531dd1c69b54632676b4be55ed046`, master from 2023-06-01)

repro:

run a script that creates & deletes cloud instances over and over again (see https://github.com/edgedb/nebula/issues/496 for an example of the script, it essentially just does instance create via the CLI, sleeps two minutes, deletes the instance, sleeps another two minutes, GOTO 10)

observed behavior:

intermittently, polling for the status of a create / delete operation will fail with an error like:

```
edgedb error: Could not destroy EdgeDB Cloud instance: HTTP error: error sending request for url (https://api.g.aws-dev-zackelan.edgedb.cloud/v1/operations/27455ca8-08c3-11ee-845c-370cf6b64520): error trying to connect: Connection reset by peer (os error 104)

or

edgedb error: Could not destroy EdgeDB Cloud instance: HTTP error: error sending request for url (https://api.g.aws-dev-zackelan.edgedb.cloud/v1/operations/f1a75360-0987-11ee-a204-e337c4c351ef): error trying to connect: Connection reset by peer (os error 104)
```

this is caused by the Nebula server being restarted about once an hour to pick up new AWS credentials, and HTTP connections being closed un-gracefully when that happens.

desired behavior:

any GET request (but particularly the loop that polls for operation status of create/delete instances) should have retry logic on a connection reset. we also want to improve this behavior on the backend to close connections more gracefully (https://github.com/edgedb/nebula/issues/541), but these errors can happen for a myriad of other reasons and I think retries from the CLI make sense.

this is not asking for retries of POST requests (such as the create/delete instance request) even though I've seen connection resets on those as well. retrying them is a thornier problem, because for example at the time the connection is reset, the backend may or may not have enqueued that operation, so a simple retry might or might not have the desired outcome.