docs: Fix nested array in telemetries example in configuration.md

[Artem-asd]

Fix incorrect nested array in telemetries example in configuration.md

This PR corrects an inconsistency in the telemetries configuration example in configuration.md.

The current example:

telemetries: [
    [
        'errors',
        'http',
        [
            'performance',
            {
                ignore: (entry: PerformanceEntry) => {
                    return entry.entryType === 'resource';
                }
            }
        ]
    ]
];

is wrapped in an unnecessary nested array, which may mislead users into thinking that all telemetry types need to be grouped inside a single array element.

Why this change is needed
Other valid examples in the same document use a flat array of telemetry definitions. For example:

telemetries: ['errors', 'performance', 'http'];

Or:

telemetries: [
    ['errors', { stackTraceLength: 500 }],
    'performance',
    ['http', { stackTraceLength: 500, addXRayTraceIdHeader: true }]
];

Or:

telemetries: [
    [
        'errors',
        {
            stackTraceLength: 500,
            ignore: (errorEvent) => {
                return (
                    errorEvent &&
                    errorEvent.message &&
                    /^Warning:/.test(errorEvent.message)
                );
            }
        }
    ],
    'performance',
    'http'
];

To stay consistent with the examples above, the updated version should be:

telemetries: [
    'errors',
    'http',
    [
        'performance',
        {
            ignore: (entry: PerformanceEntry) => {
                return entry.entryType === 'resource';
            }
        }
    ]
];

This change helps avoid confusion and ensures consistency across the documentation.