Convert invariant to warning

Author: rickhanlonii

packages/react-reconciler/src/ReactFiberWorkLoop.new.js

@@ -728,7 +728,8 @@ function ensureRootIsScheduled(root: FiberRoot, currentTime: number) {
     if (__DEV__) {
       // If we're going to re-use an existing task, it needs to exist.
       // Assume that discrete update microtasks are non-cancellable and null.
-      invariant(
+      // TODO: Temporary until we confirm this warning is not fired.
+      console['error'](
         existingCallbackNode != null ||
           newCallbackPriority === InputDiscreteLanePriority,
         'Expected scheduled callback to exist. This error is likely caused by a bug in React. Please file an issue.',

packages/react-reconciler/src/ReactFiberWorkLoop.old.js

@@ -710,7 +710,8 @@ function ensureRootIsScheduled(root: FiberRoot, currentTime: number) {
     if (__DEV__) {
       // If we're going to re-use an existing task, it needs to exist.
       // Assume that discrete update microtasks are non-cancellable and null.
-      invariant(
+      // TODO: Temporary until we confirm this warning is not fired.
+      console['error'](
         existingCallbackNode != null ||
           newCallbackPriority === InputDiscreteLanePriority,
         'Expected scheduled callback to exist. This error is likely caused by a bug in React. Please file an issue.',