Unwanted default footers/headers automatically added in CLI only

[Rachel Simone Weil]

In the CLI, it seems that Puppeteer is adding its own headers or footers depending on what flags are passed in.

This may be related to #160:

CLI command	Result
mdpdf topic.md	✅ No footers added
mdpdf topic.md --header=header.html --h-height=40px	❌ Custom header is not added. ❌ Unwanted footer is added: {File path} {Page count}
mdpdf topic.md --footer=footer.html --f-height=40px	❌ Custom footer is not added. ❌ Unwanted header is added: {Date} {Time}
mdpdf topic.md --footer=footer.html --f-height=40px --header=header.html --h-height=40px	❌ Custom header is not added. ❌ Custom footer is not added.

Notably, this does not occur when calling from the Node API.