chore: Improve portal settings validation and error handling (#12134)

# Pull Request Template

## Description

This PR includes:

1. Previously, the URL fields accepted any value starting with `https`.
Added proper URL validation to ensure valid URLs are entered.
2. Fixed an issue where form save errors displayed `[object Object]` in
the toast due to inconsistent error formatting from the backend.


Fixes https://linear.app/chatwoot/issue/CW-5389/help-center-bugs

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

### Loom video

https://www.loom.com/share/63ddca2c5e2e45c99b66153ed146524f?sid=fd25331b-6b67-4722-9b36-1213496a0741

## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

app/controllers/api/v1/accounts/portals_controller.rb

@@ -26,9 +26,8 @@ class Api::V1::Accounts::PortalsController < Api::V1::Accounts::BaseController
       @portal.update!(portal_params.merge(live_chat_widget_params)) if params[:portal].present?
       # @portal.custom_domain = parsed_custom_domain
       process_attached_logo if params[:blob_id].present?
-    rescue StandardError => e
-      Rails.logger.error e
-      render json: { error: @portal.errors.messages }.to_json, status: :unprocessable_entity
+    rescue ActiveRecord::RecordInvalid => e
+      render_record_invalid(e)
     end
   end