Fixed Global autoCreate option not applied to models on createConnection()

[KirtiGautam620]

Ensure global Mongoose options like autoCreate are inherited by additional connections

Related Issue:
Fixes #15748 – Global autoCreate option not applied to models on createConnection()

Description:
This PR addresses an issue where global Mongoose options, such as autoCreate, were not inherited by connections created via mongoose.createConnection(). Previously, only models on the default connection respected these global settings, causing inconsistent behavior between default and additional connections.

Changes Made:

• Updated the Connection constructor (lib/connection.js) to merge global options from base.options into this.options using:

  this.options = Object.assign({}, base.options);