[Feature]Add MergeOutlined icon

[kishore08-07]

Desired Behavior

Create a MergeOutlined icon in Sistent to reduce dependency on @mui/icons-material and ensure design consistency across Layer5 products.

Mockups

https://mui.com/material-ui/material-icons/?query=merg&theme=Outlined&selected=MergeOutlined

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Contributor Guide

• 🎨 Wireframes and designs for Sistent site in Figma (open invite)