[NPU] fix rope_theta get error for baichuan2-13b-chat model

[ZeyuanChen2000]

Motivation

PR sgl-project#21135 use function get_rope_config() to directly get config.rope_theta, while in model baichuan-inc/Baichuan2-13B-Chat, its config.json doesn't have this attribute.

Affected trust-remote-code models:
Baichuan2-13B-Chat

Modifications

in function get_rope_config(), provide a reasonable default(10000) value when rope_theta is missing

Accuracy Tests

Benchmarking and Profiling

Checklist

• Format your code according to the Format code with pre-commit.
• Add unit tests according to the Run and add unit tests.
• Update documentation according to Write documentations.
• Provide accuracy and speed benchmark results according to Test the accuracy and Benchmark the speed.
• Follow the SGLang code style guidance.

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@ZeyuanChen2000 , thanks for your pull request.

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[ZeyuanChen2000]

前置需要先合入PR sgl-project#21135

[Hide-on-bushsh]

approve

[qinsir5522]

approve