fix: BlockTypeDropdown can not select Heading

[prathameshjchavan]

BlockTypeDropdown can now able to select the appropriate heading as per the level of the heading.

fixes: #328

Changes:

• Changed the logic for isSelected prop
• If the block.type is 'heading', it will also check for the level of heading in block.props.level

blocknote-bug-fix.mp4

[vercel]

@prathameshjchavan is attempting to deploy a commit to the TypeCell Team on Vercel.

A member of the Team first needs to authorize it.

[matthewlipski]

Fixed in #322