When navigating to a blob, do not close the tab if a connection error occurs

[munael]

Is your feature request related to a problem? Please describe.
When the Internet's spotty it can get pretty frustrating when I'd started navigating somewhere, it keeps spinning, then errors out and just closes the tab, losing my current location.

Describe the solution you'd like
Instead of showing an error bar and closing the tab, keep the tab and indicate in the viewer area that the contents could not be fetched for X reason.

Describe alternatives you've considered
Nothing comes to mind. It's pretty basic.

Additional context
None.