Block Editor: Update callers to handle when getBlockType returns undefined

[amustaque97]

This commit has partial changes related to #34462. It is based on some manual testing.

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 since some of the usages have a few gotchas. Feel free to ask if anything I noted was unclear.

[gwwar]

Thanks for the code quality improvements @amustaque97! This one is good to land. (All tests are green and things look good with some minor smoke testing).