## Changes
The host URL for databricks workspaces includes the workspaceId by
default as a positional arg. Eg:
https://e2-dogfood.staging.cloud.databricks.com/?o=1234
Thus a user can't simply copy paste the URL today to the auth login
command. They'll see a runtime error:
```
➜ cli git:(main) ✗ databricks auth login --host https://e2-dogfood.staging.cloud.databricks.com/\?o\=xxx --profile new-dg
Error: oidc: fetch .well-known: failed to unmarshal response body: invalid character '<' looking for beginning of value. This is likely a bug in the Databricks SDK for Go or the underlying REST API. Please report this issue with the following debugging information to the SDK issue tracker at https://github.com/databricks/databricks-sdk-go/issues. Request log:
GET /login.html
...
```
## Tests
Unit tests and manually. Now auth login works even when the workspace_id
is included in the URL.
## Changes
This PR migrates `databricks auth login` HTTP client to the one from Go
SDK, making API calls more robust and containing our unified user agent.
## Tests
Unit tests left almost unchanged