Fix space formatting in cherry-pick label for flutter_cp.dart - #189463

flutter/flutter@846664b...fc1ad95

2026-07-15 [email protected] [iOS] Migrate FlutterKeyboardInsetManager to Swift (flutter/flutter#189425)
2026-07-15 [email protected] Roll Dart SDK from 05bf153370c4 to 0c408ff6dce9 (4 revisions) (flutter/flutter#189487)
2026-07-15 [email protected] Implement UberSDF lines to replace LineContents-based AA lines (flutter/flutter#188514)
2026-07-15 [email protected] Fix stale eagerWinner reference in GestureArenaManager when rejected before arena close (flutter/flutter#187008)
2026-07-15 [email protected] Disable some Windows tests that are flaking on CI (flutter/flutter#189477)
2026-07-15 dmgr Added unified check-run user manual (flutter/flutter#189453)
2026-07-15 [email protected] Roll Skia from 88954ef8f36d to ab2410bc857c (9 revisions) (flutter/flutter#189474)
2026-07-14 [email protected] [agents] Refactor shepherd-prs skill into a pure Markdown runbook using native gh CLI (flutter/flutter#189095)
2026-07-14 [email protected] Add missing name to mirroring workflow (flutter/flutter#189439)
2026-07-14 [email protected] Add support for WASM deferred loading. (flutter/flutter#189308)
2026-07-14 [email protected] fix `templateDefaultGradleVersion` todo (flutter/flutter#189466)
2026-07-14 [email protected] Roll Fuchsia Linux SDK from oOETA0ISPouDt2xBo... to lLFbh5kFWbUGgC9Ek... (flutter/flutter#189469)
2026-07-14 [email protected] Use ServicesBinding.instance.exitApplication instead of exit(0) in multiple_windows example (flutter/flutter#189364)
2026-07-14 [email protected] Add CpuArch to the Device class (flutter/flutter#189207)
2026-07-14 [email protected] Fix space formatting in cherry-pick label for flutter_cp.dart (flutter/flutter#189463)
2026-07-14 [email protected] Roll pub packages (flutter/flutter#189454)
2026-07-14 [email protected] [flutter_tools] Format plugin example template to match dart format (flutter/flutter#188382)
2026-07-14 [email protected] Move renamed x64->ARM benchmarks out of bringup (flutter/flutter#189400)

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#191123)

This pull request is created by [automatic cherry pick workflow](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md#automatically-creates-a-cherry-pick-request)
Please fill in the form below, and a flutter domain expert will evaluate this cherry pick request.

### Issue Link:
What is the link to the issue this cherry-pick is addressing?

N/A (Fixes cherry-pick helper script bug from #189463)

### Impact Description:
What is the impact (ex. visual jank on Samsung phones, app crash, cannot ship an iOS app)?
Does it impact development (ex. flutter doctor crashes when Android Studio is installed),
or the shipping of production apps (the app crashes on launch).
This information is for domain experts and release engineers to understand the consequences of saying yes or no to the cherry pick.

When running the cherry-pick agent helper script (`flutter_cp.dart`) on a release branch, the script adds unspaced label arguments (`cp:stable` or `cp:beta`) instead of `cp: stable` or `cp: beta`. This results in creating unintended, duplicate repository labels.

### Changelog Description:
Explain this cherry pick:
* In one line that is accessible to most Flutter developers.
* That describes the state prior to the fix.
* That includes which platforms are impacted.
See [best practices](https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md) for examples.

[flutter/189463] When running the cherry-pick helper script, incorrect label argument formatting causes unintended repository label creation.

### Workaround:
Is there a workaround for this issue?

Manually add the correct channel label (`cp: stable` or `cp: beta`) with a space via GitHub UI/CLI, and remove the unspaced label.

### Risk:
What is the risk level of this cherry-pick?

### Test Coverage:
Are you confident that your fix is well-tested by automated tests?

### Validation Steps:
What are the steps to validate that this fix works?

1. Run `dart .agents/skills/flutter-cherry-pick/scripts/flutter_cp.dart --pr <PR> --channel stable --action start`.
2. Verify that `cp: stable` (with space) is added to the PR and no duplicate unspaced label is created.