Changing headers on receipts and invoices.

[LanternNassi]

This pull request includes several improvements and fixes across the project, focusing on enhancing report styling, improving SQL Server installer logic, and updating project references for better reliability and compatibility.

Report Styling Updates:

• Updated invoice report styles by removing background colors and border colors from multiple textboxes in both Report1.rdlc and Invoice.rdlc, resulting in a cleaner and more consistent appearance. Also, changed the font weight for the "Product" label to ExtraBold in Report1.rdlc.

SQL Server Installer Improvements:

• Enhanced the DownloadSQL method in frmSetup.cs to check if the SQL Server installer already exists and is valid before downloading, avoiding unnecessary downloads and improving user experience.
• Fixed the installer filename in Client_DownloadFileCompleted to match the downloaded file, ensuring the correct executable is launched during installation.

Project and Dependency Updates:

• Added HintPath and Private attributes for the Microsoft.Office.Interop.Excel reference in the project file, and included a binding redirect for it in app.config to ensure correct version resolution and deployment.
• Added a reference to System.Web.Extensions in the project file to support additional web-related features.
• Minor project and configuration file cleanups, such as removing empty XML nodes and adding a missing app setting.

These changes collectively improve the reliability, maintainability, and appearance of the application.