Improve download error handling/reporting

[underscoren]

Is your feature request related to a problem? Please describe. As an end-user, when something doesn't work, it can be difficult to understand what went wrong, and why. A number of errors are only reported in the devtools console, with little to no indication in the UI.

Describe the solution you'd like Create UI elements (toasts, modals, new component state, ect as appropriate) to handle when errors occur, so the user is aware of what happened (and possibly why).

Describe alternatives you've considered The alternative would be to just continue not reporting errors to the user in a convenient and useful manner

Additional context Possible UI elements:

• Mod/pack failed to download due to API error
  • error modal with message like "Error while downloading modpack: error.msg", possible options to retry / delete broken modpack
• Mod data failed to be loaded in the background
  • error toast with message like "Error attempting to get data for modname: error.msg"

[Eskaan]

For the first, these occur internally, and it indeed gets the corresponding error message. The API Request is not failing, the code just cannot handle what it gets

But yes we may want to add a call to the error modal for failed Requests too.