CSSTUDIO-2373: fix images not displayed in some cases

[cjenkscybercom]

Summary of Changes

In some cases, images don't display properly because their mime-type is image/{something} and a few pieces of code were asserting this was equal to "image" rather than starting with that text.

I'm aware there are two places in the code performing the check, however I'd rather plan tackling that in a separate body of work.

Visual Inspection

• Conformance to Markdown styles: https://olog.esss.lu.se/Olog/help/CommonmarkCheatsheet
  • ...when viewing a log entry
  • ...when previewing HTML while writing a description
  • ...when viewing a log entry in the group view
• Scroll is possible (elements don't overflow their container, and they are scrollable)
  • ...search result list
  • ...log entry group view list
  • ...log entry single view
  • ...create new log entry page
• Overall layout fills full width and height of viewport
• Pagination element doesn't overflow into other elements

[cjenkscybercom]

Tests pass locally, please ignore flake.

[georgweiss]

How does one trigger the error case? Or, how do I verify the fix?

[cjenkscybercom]

How does one trigger the error case? Or, how do I verify the fix?

Unfortunately I've not been able to reproduce it locally, it would have shown in the end-to-end tests otherwise. But, I do know that the check on the FE is definitely not correct.

[cjenkscybercom]

Thanks Georg!