fix: modify the type of token models to be text

[xuruidong]

close #issue_number

If MySQL is used as the database, the default data type for "token models" is "varchar(191)". When we create a token object with many models, the model data string will be truncated in the database.

在使用 MySQL 作为数据库时， tokens 表中的 models 字段的类型是 varchar， 当创建 token 时配置的模型数量过多时，会导致数据不能完全保存。

有另外一个有点关系的 issue： #1483

我已确认该 PR 已自测通过，相关截图如下：
（此处放上测试通过的截图，如果不涉及前端改动或从 UI 上无法看出，请放终端启动成功的截图）

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 14 lines in your changes missing coverage. Please review.

Project coverage is 1.27%. Comparing base (f977469) to head (d7c617e).
Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
model/token.go	0.00%	14 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##            main   #1761      +/-   ##
========================================
- Coverage   1.30%   1.27%   -0.03%     
========================================
  Files        144     145       +1     
  Lines      10153   10377     +224     
========================================
  Hits         132     132              
- Misses     10007   10231     +224     
  Partials      14      14              

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[songquanpeng]

Thx~