fix: [codegeex] optimized code generate logic

[LiHua000]

Log: as title

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: LiHua000
Once this PR has been reviewed and has the lgtm label, please assign toberyan for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• debian/deepin/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 在CopilotApi::assembleGenerateBody函数中，将max_new_tokens的值从64增加到128，需要确认这是否符合API的预期限制。
• 在CopilotApi::slotReadReply函数中，对code进行了截断处理，这可能会影响某些特定格式的代码。需要确保这种处理不会破坏代码的完整性和功能。

是否建议立即修改:

• 是，需要确保max_new_tokens的更改不会导致API限制问题，并且截断代码的逻辑不会对现有功能产生负面影响。