agent: Update pieces of copy in the settings view (#35621)

Some tiny updates to make the agent panel's copywriting sharper.

Release Notes:

- N/A

crates/agent_ui/src/agent_configuration.rs

@@ -539,7 +539,7 @@ impl AgentConfiguration {
                 v_flex()
                     .gap_0p5()
                     .child(Headline::new("Model Context Protocol (MCP) Servers"))
-                    .child(Label::new("Connect to context servers via the Model Context Protocol either via Zed extensions or directly.").color(Color::Muted)),
+                    .child(Label::new("Connect to context servers through the Model Context Protocol, either using Zed extensions or directly.").color(Color::Muted)),
             )
             .children(
                 context_server_ids.into_iter().map(|context_server_id| {