fix: use correct argument name max_isl in synthesize_requests (#5441)

Signed-off-by: Dan Gil <dagil@nvidia.com>

benchmarks/prefix_data_generator/example.py

@@ -41,9 +41,9 @@ synthesizer = Synthesizer(
 # generate requests
 requests_synth = synthesizer.synthesize_requests(
     num_requests=100,
-    input_len_filter=(
+    max_isl=(
         16384 - 1000
-    ),  # this is what most model defaults to, leaving some room for outpputs
+    ),  # this is what most model defaults to, leaving some room for outputs
 )
 
 # convert the hashes into random texts (lorem ipsum), respecting the prefix structure