fix: dynamic blocks finalizing connections when children are deleted

[BeksOmega]

The basics

• [X] I validated my changes

The details

Resolves

Fixes N/A

Proposed Changes + Reasons

While writing https://github.com/google/blockly-samples/pull/2190 I discovered that delete events were not removing connections on dynamic blocks.

Previously this bug was hidden in the playground because we were finalizing connections during serialization, which triggered on every event. So delete events /were/ kind of triggering finalization, in that they were triggering serialization which triggered finalization. But when I made it so that serialization only finalized events if the inputs weren't in escalating order, the bug was revealed

Test Coverage

Manually tested that deletion triggers connections to be finalized (assuming you've properly added the change listener).

Documentation

N/A

Additional Information

N/A