[BugFix] token2wav code out of range

[Bounty-hunter]

PLEASE FILL IN THE PR DESCRIPTION HERE ENSURING ALL CHECKLIST ITEMS (AT THE BOTTOM) HAVE BEEN CONSIDERED.

Purpose

As show in #476

Talker with vocab_size 8448, while token2wav with 8193, and it will result out of range in token2wav.

Modify:
we suppress the token id [8194:8448] in talker stage.

Test Plan

Run the benchmark again!

Test Result

All Request Success

============ Serving Benchmark Result ============
Successful requests:                     100       
Maximum request concurrency:             1         
Request rate configured (RPS):           1.00      
Benchmark duration (s):                  862.52    
Total input tokens:                      16721     
Total text input tokens:                 1000      
Total generated tokens:                  6714      
Request throughput (req/s):              0.12      
Audio throughput (num/s):                0.12      
Output token throughput (tok/s):         7.78      
Peak output token throughput (tok/s):    1.00      
Peak concurrent requests:                2.00      
Total Token throughput (tok/s):          27.17     

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• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
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[hsliuustc0106]

@tzhouam @Gaohan123 is the range diffference a known problem?

[hsliuustc0106]

for qwen3-omni, does this happen?

[Bounty-hunter]

for qwen3-omni, does this happen?

Qwen3-omni may not have this problem:
talker_config.code_predictor_config.vocab_size = 2048
talker_config.code_predictor_config.num_code_groups = 16

code2wav_config.codebook_size = 2048
code2wav_config.num_quantizers = 16

It same.

[Gaohan123]

LGTM. Thanks!