[Known Issue] Relationship name and exposed field name of an entity must not overlap

note: this is a validation that should be added.

For queries (and later on for nested mutations as well), we don't have a validation in place which ensures that the relationship names and the exposed column names which belong to a particular entity (table) do not conflict with each other. In current situation, if we give same names for a relationship and an exposed column name, the engine would crash. This might be a GQL only validation since for GQL queries/mutations, relationship fields and column fields are combined. Need to evaluate where and when the validation should occur.

In the below example, there is a column named `title` in the `Book` entity and a relationship by the same name as well.

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