get Html Media Load Timeout Milliseconds
The maximum time, in milliseconds, to wait for page media (images and other sub-resources) to finish loading when rendering HTML, MHTML, or email input, before the page is captured. When set to a positive value, the renderer waits for the load event but no longer than this many milliseconds, so a slow or unreachable external resource cannot stall the conversion.
Return
The value of the HtmlMediaLoadTimeoutMilliseconds property.