Code Quality: Fixed inverted if statement from #16141

Author: yaira2

src/Files.App/Utils/Git/GitHelpers.cs

@@ -647,7 +647,7 @@ public static bool IsRepositoryEx(string path, out string repoRootPath)
 			if (string.IsNullOrEmpty(repositoryRootPath))
 				return false;
 
-			if (!IsRepoValid(repositoryRootPath))
+			if (IsRepoValid(repositoryRootPath))
 			{
 				repoRootPath = repositoryRootPath;
 				return true;