feat: change Flutter engine to fallback to base when patch can't load (without crashing)

[eseidel]

Currently if a patch fails to boot we will crash the app. I suspect we don't need to do that.

I'm not entirely sure how hard it will be to change the flutter engine, but: https://github.com/shorebirdtech/engine/blob/655974aed33b608d1075cffae0fcaf06772d90d8/shell/common/shell.cc#L148

I think we can just revert the settings back to the unpatched version and try a second time and continue?