[RNMobile] Remove parent block's icon from floating toolbar

[fluiddot]

Description

Remove the icon of the parent block from the floating toolbar that is displayed when navigating inner blocks.

This change was originated while working on the reusable block feature, @iamthomasbishop mentioned that we were considering if this part is actually creating value and/or causing confusion to users.

How has this been tested?

1. Open a post
2. Add any block that has inner blocks (for example the Group block)
3. Add some blocks in the Group block
4. Select one of the inner blocks
5. Observer that the parent icon of the parent block is not displayed.

Screenshots

Before	After

Types of changes

Enhancement

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).

[youknowriad]

Doing some cleanup to old PRs. This draft PR seems staled. Is it still relevant, should we close it?

[fluiddot]

Doing some cleanup to old PRs. This draft PR seems staled. Is it still relevant, should we close it?

Yes, it's no longer relevant so I'll close it. Thanks @youknowriad for the call out 🙇 !