Introduce SkipUtils and Refactor Skip Logic

[Atralupus]

Many tests currently use repetitive logic to skip tests with Assert.Skip. To improve maintainability and reduce redundancy, a utility method SkipUtils.ExecuteWithSkipAsync should be introduced and applied across the codebase.

Implementation Example:

namespace MimirUptime;

public static class SkipUtils
{
    public static async Task<T> ExecuteWithSkipAsync<T>(
        Func<Task<T>> requestFunc,
        string skipMessage
    )
    {
        try
        {
            return await requestFunc();
        }
        catch (Exception)
        {
            Assert.Skip(skipMessage);
            throw;
        }
    }
}

Application Example:

public async Task<int> GetHeadlessActionPointData(long blockIndex, Address avatarAddress)
{
    var stateResponse = await SkipUtils.ExecuteWithSkipAsync(
        async () => await headlessClient.GetState.ExecuteAsync(
            Addresses.ActionPoint.ToString(),
            avatarAddress.ToString(),
            blockIndex
        ),
        "Headless client is unresponsive; skipping test."
    );
    var result = CodecUtil.DecodeState(stateResponse.Data.State);
    
    if (result is not Integer value)
        throw new Exception();

    return value;
}

Refactor all relevant tests to use this utility method.