Feature: Optional, re-sizable side dialog.

[artnim]

Is your feature request related to a problem? Please describe.
The current Side Dialog has a fixed width. In some scenarios, especially when displaying complex content such as forms, grids, or editors, users may need to adjust the dialog size for better visibility or usability.

Describe the solution you'd like
Introduce an optional Resizable parameter to SideDialogOptions.
When set to true, the dialog displays a resize handle on the corresponding side (depending on the Position parameter). Users can adjust the width/height interactively, with support for min/max constraints via CSS.
The default remains false to ensure backward compatibility.

Describe alternatives you've considered
Manually wrapping the dialog in a resizable container or adjusting its width via JavaScript and CSS. These workarounds are less reliable and inconsistent with built-in Radzen behavior.

Additional context
The implementation is available in PR #2331.
It introduces a minimal, self-contained enhancement that preserves existing behavior.