Fix FileDialog default size

[Giganzo]

Fixes: #58780

Before:

After:

[WhalesState]

This change should be added to the FileDialog.xml to paypass the checks,
You can open the failed check and copy the line to the same place in the XML file.

The proper way is to use the --doctool from cmd.

path/to/godot-source-code/bin/./godot.exec --doctool path/to/godot-source-code/

If you are using VSCode, you can edit and use this build task.

{
    "label": "build docs",
    "group": "build",
    "type": "shell",
    "command": "${workspaceFolder}/bin/./godot.windows.editor.x86_64.exe --doctool ${workspaceFolder}/"
}

[KoBeWi]

The new default size makes the dialog much more usable. I tested and it works correctly with scaling enabled too.

[akien-mga]

Thanks!