Added progress bar when changing type on multiple nodes

[pouleyKetchoupp]

This change displays a progress bar while doing operations instead of freezing the editor

The progress bar also flushes the message queue, which fixes these errors in cases with lots of nodes:

ERROR: push_call: Message queue out of memory. Try increasing 'message_queue_size_kb' in project settings.
   At: core/message_queue.cpp:56.

Fixes #23853

[Calinou]

Looking at the code, it seems a progress bar is displayed as soon as there are at least 2 nodes in the selection. Since it's usually recommended not to display a progress bar for very short actions, should this minimum be increased? Changing the type of 5 nodes likely won't take more than a second on most hardware.

[pouleyKetchoupp]

Right now, it's displayed as long as more than one node is selected (there are 2 actions for each node). I'll make more tests to display it only when it takes more time to process.

[pouleyKetchoupp]

The time it takes to process node replacements also depends on how many nodes are present in the scene, but I've changed it to something more reasonable. Now it will trigger the progress bar for more than 10 nodes (and refresh on every 10th node).

[akien-mga]

EditorProgress is known to cause some issues and slowdowns, so this needs to be reviewed properly. Haven't done so yet, but just mentioning why it hasn't been merged yet :)

This also seems to handle quite a corner case, so I'm not sure it's worth adding this to UndoRedo.

[pouleyKetchoupp]

Alright, thanks for the heads up!

I just wanted to point out that the stuff in UndoRedo might help in the future to solve more cases of operations causing the message queue to be out of memory :)

[aaronfranke]

@pouleyKetchoupp Is this still desired? If so, it needs to be rebased on the latest master branch.

[pouleyKetchoupp]

The issue this PR fixes is related to #35653, so for 4.0 it's going to be fixed using a different approach.

I'm closing since it's probably too much of a corner case to be cherry-picked for 3.2.