Fix duplicate validation errors for GenericIPAddressField with protocol (#10011)

* Fix duplicate validation errors for GenericIPAddressField with protocol

When a Django model uses GenericIPAddressField(protocol='IPv4') or
(protocol='IPv6'), the model field gets a protocol-specific validator
(validate_ipv4_address or validate_ipv6_address) from Django. DRF's
IPAddressField also adds the same validator via ip_address_validators(),
resulting in duplicate error messages.

Fix: Remove validate_ipv4_address and validate_ipv6_address from the
serializer's validator_kwarg, in addition to the already-removed
validate_ipv46_address.

Fixes #9645

* Extend test coverage to validate error messages too

* Add test with unhashable type validator

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Co-authored-by: justyou0606 <justyou0606@users.noreply.github.com>