[FIX] component, fiber: error_handling at the Fiber level

Before this commit, errors triggered at the level of the fiber (as opposed to at the level
of a component's rendering), were handled as the very top level of the rendering, that is,
in the scheduler.
This was wrong because components below in the rendering tree would not have a chance to handle their
children's or their own errors.

After this commit, error triggered in willPatch, onMounted and onPatched are correctly handled
at the closest component to where they were thrown.

src/component/scheduler.ts

@@ -1,5 +1,5 @@
 import { Fiber, RootFiber } from "./fibers";
-import { handleError, fibersInError } from "./error_handling";
+import { fibersInError } from "./error_handling";
 import { STATUS } from "./status";
 
 // -----------------------------------------------------------------------------
@@ -60,13 +60,8 @@ export class Scheduler {
 
       if (fiber.counter === 0) {
         if (!hasError) {
-          try {
-            fiber.complete();
-            fiber.resolve();
-          } catch (e) {
-            handleError(fiber.node, e);
-            fiber.reject(e);
-          }
+          fiber.complete();
+          fiber.resolve();
         }
         this.tasks.delete(fiber);
       }