Fix import path for trust_remote_code loading

Replace `from hf.configuration_hybridna` with relative import
`from .configuration_hybridna` so the model loads correctly via
AutoModel.from_pretrained(..., trust_remote_code=True).

modeling_hybridna.py

@@ -53,7 +53,7 @@ from transformers.utils.import_utils import (
     is_flash_attn_2_available,
     is_mamba_ssm_available,
 )
-from hf.configuration_hybridna import HybriDNAConfig
+from .configuration_hybridna import HybriDNAConfig
 from mamba_ssm.ops.triton.layernorm_gated import RMSNorm as RMSNormGated
 
 # try except block so it'll work with trust_remote_code.