Remove obsolete APIs from Components

[mkArtakMSFT]

See #3654 for details.

(43) src\Components\Components\src\Json\JsonUtil.cs

Links: [master] | [release/2.2]
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    [Obsolete("Use Microsoft.JSInterop.Json instead.")]
    public static class JsonUtil
    {

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(44) src\Components\Components\src\Json\JsonUtil.cs

Links: [master] | [release/2.2]
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        [Obsolete("Use Microsoft.JSInterop.Json.Serialize instead.")]
        public static string Serialize(object value)
            => Json.Serialize(value);

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(45) src\Components\Components\src\Json\JsonUtil.cs

Links: [master] | [release/2.2]
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        [Obsolete("Use Microsoft.JSInterop.Json.Deserialize<T> instead.")]
        public static T Deserialize<T>(string json)
            => Json.Deserialize<T>(json);

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