bug: q login always prompts for start url and region even if the --identity-provider and --region are provided

### Checks

- [x] I have searched [github.com/aws/amazon-q-developer-cli/issues](https://github.com/aws/amazon-q-developer-cli/issues?q=) and there are no duplicates of my issue
- [x] I have run `q doctor` in the affected terminal session
- [x] I have run `q restart` and replicated the issue again

### Operating system

MacOS

### Expected behaviour

(This is a parallel of https://github.com/aws/amazon-q-developer-cli/issues/2659, requested to be submitted in parallel by that project's maintainer).

When "q login" is supplied with --license pro, --identity-provider with value, and --region with value, q presents the confirmation URL without requiring the user to enter the identity provider URL and the region.

### Actual behaviour

"q login" still asks for the values for the identity provider and region - they are pre-filled, but still require user confirmation.

### Steps to reproduce

Run q logout (if previously logged in)
Run q login --license pro --identity-provider "https://your-identity-center.awsapps.com/start" --region us-east-1 --use-device-flow
Observe that the command prompts for confirmation despite providing the parameters. They are pre-filled, but still require user confirmation.

### Environment

```yaml
[q-details]
version = "1.15.0"
hash = "eb8db5c635fc469f3bd94ead16bb4bfb32d7443b"
date = "2025-09-02T17:57:24.662205Z (6d ago)"
variant = "full"

[system-info]
os = "macOS 15.6.1 (24G90)"
chip = "Apple M3"
total-cores = 8
memory = "16.00 GB"

[environment]
cwd = "/Users/USER"
cli-path = "/Users/USER"
os = "Mac"
shell-path = "/bin/zsh"
shell-version = "5.9"
terminal = "macOS"
install-method = "unknown"

[env-vars]
PATH = "/Users/USER/.config/q:/Users/USER/.local/bin:/usr/local/mysql/bin:/opt/local/bin:/usr/local/opt/node/bin:/usr/local/opt/python@3.13/libexec/bin:/Users/USER/Library/Python/3.11/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/Users/USER/.cargo/bin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Library/Apple/usr/bin:/usr/local/share/dotnet:~/.dotnet/tools:/Library/Frameworks/Mono.framework/Versions/Current/Commands:/Applications/Xamarin Workbooks.app/Contents/SharedSupport/path-bin:/Users/USER/.local/bin:/usr/local/bin:/usr/local/sbin"
QTERM_SESSION_ID = "4c8b2d3909214cf892c0d4d940d0faed"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "1.15.0"
SHELL = "/bin/bash"
TERM = "xterm-256color"
__CFBundleIdentifier = "com.apple.Terminal"
```