Improve site status check for json format

[nightnei]

How AI was used in this PR

AI helped to write the code and we had a few iterations to adjust teh approach

Proposed Changes

1. For site status --format=json we receive emoji which doesn't make sense for machine-readable output and it forces to use .includes('Online') instead of direct check via === 'Online'
2. We have localization, so it complicates a lot the condition. As a workaround so far, I found out that we can check for existance of autoLoginUrl, but it's jsut workaround.

So I propose to introduce isOnline: boolean for json.

Testing Instructions

1. npm run cli:build
2. node apps/cli/dist/cli/main.mjs site status --path=~/Studio/my-wordpress-website --format=json
3. Assert that you see isOnline: boolean
4. node apps/cli/dist/cli/main.mjs site status --path=~/Studio/my-wordpress-website
5. Assert that no regresion and you don't see isOnline: boolean

[wpmobilebot]

📊 Performance Test Results

Comparing 260fef0 vs trunk

app-size

Metric	trunk	260fef0	Diff	Change
App Size (Mac)	1409.62 MB	1409.62 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	260fef0	Diff	Change
load	1506 ms	1496 ms	10 ms	⚪ 0.0%

site-startup

Metric	trunk	260fef0	Diff	Change
siteCreation	8566 ms	8572 ms	+6 ms	⚪ 0.0%
siteStartup	4927 ms	4920 ms	7 ms	⚪ 0.0%

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Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)