Fix disconnect reconnect

[khanak0509]

Fixes #9838

This PR fixes issue #9838 where the DevTools Inspector was getting stuck disconnected after the Mac went to sleep and woke back up, like it just showed a dead Run a new debug session to reconnect message with no actual way to reconnect, even though the app was still running fine the whole time.

I added a Reconnect button to the disconnected overlay that reuses the last known VM service URI to reconnect, so you don't have to restart your whole debug session just because your laptop slept

issue.mov

Pre-launch Checklist

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[gemini-code-assist]

Code Review

This pull request introduces a manual 'Reconnect' button to the disconnected screen in DevTools, allowing users to attempt reconnection to the last known VM service. Feedback on the changes highlights two key improvements: first, guarding the reconnection process against concurrent attempts since Dart's Future.timeout() does not cancel the underlying operation, and second, replacing the raw string 'uri' with the established named constant DevToolsQueryParams.vmServiceUriKey to comply with the repository's style guide.

[srawlins]

Thanks!