Feature request: Metrics support setting functionName

[hjgraca]

Use case

Currently we cannot set the FunctionName in metrics as this value is added as dimension from the lambda context.
This can cause issues when the names are auto generated by infra tools or top level statements lambdas

Related to issue: aws-powertools/powertools-lambda-typescript#3642

Solution/User Experience

Support setting FunctionName

Decorator

[Metrics(Namespace = "ns", Service = "svc", CaptureColdStart = true, FunctionName= "MyFunctionName")]
 public void HandleWithParamAndLambdaContext(string input, ILambdaContext context)
 {
        
 }

Configure

    Metrics.Configure(options =>
    {
       options.FunctioName = "MyFunctionName";
        options.Namespace = "dotnet-powertools-test";
        options.Service = "testService";
        options.CaptureColdStart = true;
        options.DefaultDimensions = new Dictionary<string, string>
        {
            { "Environment", "Prod" },
            { "Another", "One" }
        };
    });

Builder

_metrics = new MetricsBuilder()
        .WithFunctionName("MyFunctionName")
        .WithCaptureColdStart(true)
        .WithService("testService")
        .WithNamespace("dotnet-powertools-test")
        .WithDefaultDimensions(new Dictionary<string, string>
        {
            { "Environment", "Prod1" },
            { "Another", "One" }
        }).Build();

Alternative solutions

Acknowledgment

• This feature request meets Powertools for AWS Lambda (.NET) Tenets
• Should this be considered in other Powertools for AWS Lambda languages? i.e. Python, Java, and TypeScript