Validate file size before upload

[SahithiAmmana]

Fixes #7382

Short description of what this resolves:

This pull request addresses the issue where OpenEMR fails to display an error message when attempting to upload large files, leaving users unaware of the upload failure.

Changes proposed in this pull request:

• Implemented client-side file size validation using JavaScript to prevent submission of files exceeding the maximum size limit.
• Modified the upload form in "./templates/documents/general_upload.html" to incorporate the checkFileSize() JavaScript function.
• Updated the "onsubmit" attribute of the form element to trigger the checkFileSize() function before form submission, ensuring validation occurs prior to data submission to the server.