feat: add show_filters_icon property to Link for controlling Web UI filter icon display

This commit adds a new `show_filters_icon` property to the Link class, allowing users to control whether filter icons are displayed in the Web UI at the individual link level.

**Changes:**
- Added `_show_filters_icon` attribute to Link class (default: True)
- Added `show_filters_icon` property getter
- Added `update_show_filters_icon()` method for updating the property
- Updated `asdict()` to include the new field in both topology and regular dumps
- Added `show_filters_icon` field to LinkBase schema
- Updated API routes to handle the new field in create and update operations

**API Impact:**
- POST /v3/projects/{project_id}/links - accepts `show_filters_icon` in request body
- PUT /v3/projects/{project_id}/links/{link_id} - can update `show_filters_icon`
- GET /v3/projects/{project_id}/links/{link_id} - returns `show_filters_icon` field

**Future Applications:**
This feature provides granular control for future AI fault injection modules to manage link-level protocol failures while maintaining clean UI presentation.

gns3server/api/routes/controller/links.py

@@ -107,6 +107,8 @@ async def create_link(project_id: UUID, link_data: schemas.LinkCreate) -> schema
         await link.update_link_style(link_data["link_style"])
     if "suspend" in link_data:
         await link.update_suspend(link_data["suspend"])
+    if "show_filters_icon" in link_data:
+        await link.update_show_filters_icon(link_data["show_filters_icon"])
     try:
         for node in link_data["nodes"]:
             await link.add_node(
@@ -171,6 +173,8 @@ async def update_link(link_data: schemas.LinkUpdate, link: Link = Depends(dep_li
         await link.update_link_style(link_data["link_style"])
     if "suspend" in link_data:
         await link.update_suspend(link_data["suspend"])
+    if "show_filters_icon" in link_data:
+        await link.update_show_filters_icon(link_data["show_filters_icon"])
     if "nodes" in link_data:
         await link.update_nodes(link_data["nodes"])
     return link.asdict()