fix(schema): add missing json tag for ToolArgument.Text field

[zhuangjie1125]

What type of PR is this?

Check the PR title.

• This PR title match the format: <type>(optional scope): <description>
• The description of this PR title is user-oriented and clear enough for others to understand.
• Attach the PR updating the user documentation if the current PR requires user awareness at the usage level. User docs repo

(Optional) Translate the PR title into Chinese.

(Optional) More detailed description for this PR(en: English/zh: Chinese).

en:
add missing json tag for ToolArgument.TextArgument field

(Optional) Which issue(s) this PR fixes:

(optional) The PR that updates user documentation:

[codecov]

Codecov Report

❌ Patch coverage is 42.85714% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.52%. Comparing base (32fc2fb) to head (3b23a0f).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
components/tool/utils/invokable_func.go	0.00%	2 Missing ⚠️
components/tool/callback_extra.go	0.00%	1 Missing ⚠️
components/tool/utils/streamable_func.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #766   +/-   ##
=======================================
  Coverage   80.52%   80.52%           
=======================================
  Files         129      129           
  Lines       13007    13007           
=======================================
  Hits        10474    10474           
+ Misses       1733     1731    -2     
- Partials      800      802    +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.