String pattern in ID field not taken into account

[leplatrem]

Steps to reproduce

• Create a collection with a JSON schema:

"schema": {
  "properties": {
    "id": {
      "type": "string",
      "pattern": "^[0-7]$"
    },
    "title": {
      "title": "Title",
      "type": "string",
      "pattern": "^[0-7]$",
      "description": "Short title"
    }
}

• Post a record {"id": "abc", "title": "1"}

Expected

• the record should be rejected because id field does not match pattern

Actual behaviour

• pattern is verified on the title field, but not on id

See:

kinto/kinto/views/records.py

Lines 63 to 69 in 239deea

	# Remove internal and auto-assigned fields from schemas and record.
	internal_fields = (
	self.model.id_field,
	self.model.modified_field,
	self.schema_field,
	self.model.permissions_field,
	)