[ChangesReporting] Fix total changed result on --no-diffs on JsonOutputFormatter

[samsonasik]

Fixes rectorphp/rector#9582

Even with --no-diffs, the total files changed should still be shown, just no diff to be shown.

With a 1 file to be changed, it shows:

Before

➜  rector-src git:(main) ✗ ./bin/rector process src/Application/FileProcessor.php --output-format=json --no-diffs --dry-run

{
    "totals": {
        "changed_files": 0,
        "errors": 0
    }
}

After

➜  rector-src git:(fix-total-changed) ./bin/rector process src/Application/FileProcessor.php --output-format=json --no-diffs --dry-run

{
    "totals": {
        "changed_files": 1,
        "errors": 0
    }
}

[samsonasik]

Fixed 🎉 /cc @peterfox

[samsonasik]

@TomasVotruba ready 👍

[peterfox]

Amazing @samsonasik I was looking at this, my fix was way more converluted 😄. Thank you so much

[TomasVotruba]

LGTM 👍

[peterfox]

The only thing I will add is, the way the formatter currently works, you lose the "changed_files" part of the JSON. Some might expect to still see this if the --no-diffs flag is used

    "changed_files": [
        "some/file.php"
    ],

[TomasVotruba]

@peterfox Seems legit. Could you make a PR for it?