Fix for object rendering in HITL interface

[stuart23]

HITL Approve UI does not correctly display object DAG parameters. These were being displayed as [object Object] (see below).

Main change (hitl.ts):

• Added support for preloading parameter values from URL query strings
• Added JSON parsing for string values that look like JSON objects
• Fixed type detection to correctly identify object parameters (instead of defaulting to string)
  Test file (hitl.test.ts):
• New test verifying object parameters are typed as 'object'

---

^ Add meaningful description above
Read the Pull Request Guidelines for more information.
In case of fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in a newsfragment file, named {pr_number}.significant.rst or {issue_number}.significant.rst, in airflow-core/newsfragments.

[bbovenzi]

Thanks for adding a test too!

[github-actions]

Backport failed to create: v3-1-test. View the failure log Run details

Status	Branch	Result
❌	v3-1-test

You can attempt to backport this manually by running:

cherry_picker caab2a9 v3-1-test

This should apply the commit to the v3-1-test branch and leave the commit in conflict state marking
the files that need manual conflict resolution.

After you have resolved the conflicts, you can continue the backport process by running:

cherry_picker --continue

[stuart23]

Thanks for adding a test too!

You know I always do! 😉