Update Callers to handle when getBlockType return undefined

[amustaque97]

Description

In most cases we either need to check if blockType is truthy before using it, or use optional chaining if it makes sense. eg const icon = blockType?.icon;

How has this been tested?

Testing Instruction can be found here #34346 (comment)

Screenshots

Types of changes

Fix

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).

cc @gwwar

[gwwar]

Thanks for taking a look @amustaque97! I left a few notes.

[gwwar]

This PR is part of #34462

To manually test this, create a new post, and in the code editor add:

<!-- wp:foo /-->

Go back to code view, and we should see the missing block:

Unregister the missing block type in console:

wp.data.dispatch('core/blocks').removeBlockTypes('core/missing')

Try doing some actions like going to code view or trying to click the missing block. Theoretically the editor should not WSOD, or throw a JS error (from any of the areas this PR has updated).

[gwwar]

This one just needs one more change and it should be good to land! Sorry for the delay @amustaque97

I also verified in manual testing that we didn't see any errors related to code changes here when unregistering the missing blockType

[amustaque97]

@gwwar, I have addressed review comments. Please take a look once you get some time.

[gwwar]

Thanks for your work here @amustaque97! I'll land this once we get a clean test run ✅