influxdb 2.0 authorization token required mandatorily

environment
```
influxdb: 1.8 (auth disabled)
inch: latest
```
can't run inch without auth token
```
root@9df1bf7dfbc4:/# inch -host http://10.43.142.118:8086
Host: http://10.43.142.118:8086
Concurrency: 1
Virtual Hosts: 0
Measurements: 1
Tag cardinalities: [10 10 10]
Points per series: 100
Total series: 1000
Total points: 100000
Total fields per point: 1
Randomized field values: false
Multiple writes per point: false
Batch Size: 5000
Database: stress (Shard duration: 7d)
Write Consistency: any
Writing into InfluxDB 2.0: false
InfluxDB 2.0 Authorization Token:
```

No file or test is named. Reproduce the command against InfluxDB 1.8 with authentication disabled, then trace where the authorization token is requested. Done means inch can run without requiring a token in this configuration, with a regression test for the behavior.

Written by the indexing model from the issue text.