Prepare for 4.6.0 release

[HeshanSudarshana]

Purpose

This pull request finalizes the release of version 4.6.0 for WSO2 API Manager, Control Plane, and Universal Gateway, updating documentation, metadata, and dependency versions across the codebase. The changes remove "-Beta" references, update release dates, and align all product and dependency versions with the official 4.6.0 release.

Release documentation and metadata updates:

• Updated all release note files (release-notes.html, release-notes.xml) and related documentation to reflect the official 4.6.0 release, replacing "-Beta" with "Released" and updating the release date to "16th October 2025". [1] [2] [3] [4] [5]
• Changed headings and GitHub milestone links in release notes to refer to "Bug Fixes And Improvements in 4.6.0" and updated issue tracking URLs for more comprehensive milestone coverage. [1] [2] [3] [4] [5]

Version alignment and dependency upgrades:

• Updated product and Carbon framework versions in configuration files (filter.properties, carbon.product) for all distributions to 4.9.31. [1] [2] [3] [4]
• Upgraded key dependencies in pom.xml files for API Manager and Control Plane, including carbon.apimgt.ui, carbon.apimgt, carbon.identity, carbon.kernel, synapse, axis2.wso2, and various key manager features. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]

These updates ensure all documentation, metadata, and dependencies are consistent with the official 4.6.0 release, preparing the codebase for general availability.