Navigation: Add pluginId to standalone plugin page NavLinks (#57769)

* feat(Navigation): add `pluginId` to NavLink and override sibling navlinks with the same URL

* test replacing page from plugin

* chore: fix go lint issues

* fix(NavLink): change `PluginId` to `PluginID`

Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

* fix(NavLink): make the `PluginId` -> `PluginID` change everywhere

* chore(navModel.ts): update explanatory comment for `pluginId`

Co-authored-by: Miklós Tolnai <miklos.tolnai@grafana.com>
Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

pkg/services/navtree/models.go

@@ -67,6 +67,7 @@ type NavLink struct {
 	HighlightText    string     `json:"highlightText,omitempty"`
 	HighlightID      string     `json:"highlightId,omitempty"`
 	EmptyMessageId   string     `json:"emptyMessageId,omitempty"`
+	PluginID         string     `json:"pluginId,omitempty"` // (Optional) The ID of the plugin that registered nav link (e.g. as a standalone plugin page)
 }
 
 func (node *NavLink) Sort() {