Fix extract_sequence function signature for Gradio compatibility

The function was expecting a tuple but Gradio passes arguments separately

app.py

@@ -271,8 +271,7 @@ def score_and_create_matrix_all_singles(sequence,mutation_range_start=None,mutat
     
   return score_heatmaps, suggest_mutations(scores), csv_files
 
-def extract_sequence(example):
-  label, taxon, sequence = example
+def extract_sequence(protein_id, taxon, sequence):
   return sequence
 
 def clear_inputs(protein_sequence_input,mutation_range_start,mutation_range_end):