Allow uniqueness validation between blocks in modular content field

Currently when one uses modular content field with multiple blocks, there is no way to specify that each block needs to have a unique value in certain field.

In our use case we have modular field that allows to host multiple “Item“ blocks. Each “Item“ block has a “name“ field. We need to enforce that when editor adds “Item“, each has unique name (just among each other, not globally)