Refactor: Remove unnecessary using directives across multiple files

- Cleaned up code by removing unused using directives from various test and implementation files in the trends and volume directories.
- This includes files related to HMA, HTIT, JMA, KAMA, LSMA, MAMA, MGDI, PWMA, RMA, SMA, SSF, SUPER, T3, TEMA, TRIMA, USF, VIDYA, WMA, ATR, ADL, and ADOSC.
- Improved code readability and maintainability by streamlining imports.

lib/volatility/atr/Atr.Quantower.Tests.cs

@@ -1,4 +1,3 @@
-using Xunit;
 using TradingPlatform.BusinessLayer;
 using QuanTAlib;
 

lib/volatility/atr/Atr.Validation.Tests.cs

@@ -1,13 +1,9 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using OoplesFinance.StockIndicators;
 using OoplesFinance.StockIndicators.Enums;
 using OoplesFinance.StockIndicators.Models;
 using Skender.Stock.Indicators;
 using TALib;
 using Tulip;
-using Xunit;
 using Xunit.Abstractions;
 
 namespace QuanTAlib.Tests;