WPF-880302 : Add code snippets example for Selecting item using SelectedItem and SelectedIndex in Accordion control

[ghost]

Description:
Added the code snippets example for Selecting item using SelectedItem and SelectedIndex in Accordion control.

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: WPF-880302-Need-to-add-code-snippets-example-for-Selecting-item-using-SelectedItem-and-SelectedIndex-in-Accordion

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: WPF-880302-Need-to-add-code-snippets-example-for-Selecting-item-using-SelectedItem-and-SelectedIndex-in-Accordion
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
FT Layout Syntax Error(s): 0
Front matter Error(s): 0
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0