Deep assign/delete a field inside `any` schema type

[TarantoolBot]

Since: 3.7

Root document: https://www.tarantool.io/en/doc/latest/reference/reference_lua/config/utils_schema/#lua-function.schema_object.set

Important

The `data` argument is assumed to be validated against the given schema.
The `value` argument is validated before assignment.

+ For schema nodes of the `scalar({ type = 'any' })` type, no structural
+ validation is performed. Such nodes are treated as schemaless containers,
+ so assigning or deleting nested fields via deep paths is allowed.

Requested by @mandesero in tarantool/tarantool@1e3c241.