fix(web-app): clear dependent param value when condition not met (#2298)

[DSingh0304]

What's changed?

Fixes #2298.

Root Cause:
In MonitorFormComponent, when onDependChanged hid dependent fields (such as payload when switching httpMethod from POST/PUT to GET), it set display = false without clearing paramValue. As a result, the previous payload data remained in the form state and was submitted on detect/save, causing HTTP 415/400 errors on GET requests.

Changes:

1. Updated onDependChanged to reset param.paramValue = null whenever a dependent field's condition is not met.
2. Dynamically recomputed hasAdvancedParams to correctly reflect the advanced fields' visibility state.
3. Added (ngModelChange) event binding for advancedParamDefines to ensure changes in advanced fields also trigger dependency checks.
4. Added unit tests in monitor-form.component.spec.ts covering dependency hiding and clearing behavior.

Checklist

• I have read the Contributing Guide
• I have written the necessary doc or comment.
• I have added the necessary unit tests and all cases have passed.

Add or update API

• I have added the necessary e2e tests and all cases have passed.