🔐 fix: Secure iconURL Handling (#10753)

* 🔒 fix: `iconURL` in conversation parsing

- Updated the `buildEndpointOption` middleware to derive `iconURL` from model specs when not provided by the client, improving security by preventing malicious URLs.
- Modified the `parseCompactConvo` function to strip `iconURL` from conversation inputs, ensuring it is only set server-side.
- Added comprehensive tests to validate the stripping of `iconURL` across various endpoint types, enhancing overall input sanitization.

* ✨ feat: Add ESLint rule for unused variables

- Introduced a new ESLint rule to warn about unused variables, allowing for better code quality and maintainability.
- Configured the rule to ignore variables and arguments that start with an underscore, accommodating common coding practices.

eslint.config.mjs

@@ -269,6 +269,16 @@ export default [
         project: './packages/data-provider/tsconfig.json',
       },
     },
+    rules: {
+      '@typescript-eslint/no-unused-vars': [
+        'warn',
+        {
+          argsIgnorePattern: '^_',
+          varsIgnorePattern: '^_',
+          caughtErrorsIgnorePattern: '^_',
+        },
+      ],
+    },
   },
   {
     files: ['./api/demo/**/*.ts'],