agent: Expose web search tool to beta users (#29273)

This gives all beta users access to the web search tool

Release Notes:

- agent: Added `web_search` tool

crates/language_model/src/registry.rs

@@ -42,6 +42,10 @@ impl ConfiguredModel {
     pub fn is_same_as(&self, other: &ConfiguredModel) -> bool {
         self.model.id() == other.model.id() && self.provider.id() == other.provider.id()
     }
+
+    pub fn is_provided_by_zed(&self) -> bool {
+        self.provider.id().0 == crate::ZED_CLOUD_PROVIDER_ID
+    }
 }
 
 pub enum Event {