.Net: Improve logging for function calls processor and kernel function

[SergeyMenshykh]

Motivation, Context and Description

This PR improves the existing logging functionality in both FunctionCallsProcessor and KernelFunction by logging additional contextual information, such as function details, function choice behavior configuration, and function call details, to simplify troubleshooting.

[TaoChenOSU]

If PluginName is null, will the message become "Function -{FuctionName} invoking" or "Function Null-{FunctionName} invoking"?

[SergeyMenshykh]

If the plugin name is not provided and the function name is Function1, the log message will be: "Function (null) - Function1 invoking."

The message template can be slightly changed to better communicate that no plugin is provided. The log entry message would be: "Function(PluginName:(null), Name:Function1) invoking." if the plugin name is null.

If neither of the messages looks right, the source generated methods that produces logs above:

[LoggerMessage(
    EventId = 0,
    Level = LogLevel.Information,
    Message = "Function {PluginName}-{FunctionName} invoking.")]
public static partial void LogFunctionInvoking(
    this ILogger logger,
    string? pluginName,
    string functionName);

can be replaced by two actions and one method to handle the null plugin names:

/// <summary>
/// Action to log invocation of a <see cref="KernelFunction"/>.
/// </summary>
private static readonly Action<ILogger, string, string, Exception?> s_logPluginFunctionInvocation =
    LoggerMessage.Define<string, string>(
        logLevel: LogLevel.Information,
        eventId: 0,
        formatString: "Function {PluginName}-{FunctionName} invoking.",
        options: new LogDefineOptions { SkipEnabledCheck = true });

/// <summary>
/// Action to log invocation of a <see cref="KernelFunction"/>.
/// </summary>
private static readonly Action<ILogger, string, Exception?> s_logFunctionInvocation =
    LoggerMessage.Define<string>(
        logLevel: LogLevel.Information,
        eventId: 0,
        formatString: "Function {FunctionName} invoking.",
        options: new LogDefineOptions { SkipEnabledCheck = true });

/// <summary>
/// Logs invocation of a <see cref="KernelFunction"/>.
/// </summary>
public static void LogFunctionInvoking(this ILogger logger, string? pluginName, string functionName)
{
    if (logger.IsEnabled(LogLevel.Information))
    {
        if (!string.IsNullOrEmpty(pluginName))
        {
            s_logPluginFunctionInvocation(logger, pluginName!, functionName, null);
        }
        else
        {
            s_logFunctionInvocation(logger, functionName, null);
        }
    }
}

[TaoChenOSU]

same question as above, also in a couple other places.