Plug-ins: the clear-cache test installs with request grants allowed

plugin.install refuses grant from a request unless the session was started
to allow it, so the test from main that installs with grant turns that on.
The install dialog's comment names OK's Sense::click.

crates/engine/tests/plugin_clear_cache.rs

@@ -40,6 +40,7 @@ fn clearing_every_cache_empties_each_plugins_cache_and_keeps_its_settings() {
     std::fs::create_dir_all(&folder).unwrap();
     let ids = ["test.clearcache.a", "test.clearcache.b"];
     let mut s = Session::new();
+    s.allow_plugin_grants_from_requests();
     s.execute("file.new", &json!({"width": 400, "height": 200})).unwrap();
     s.attach_plugin_store(folder.clone());
     for id in ids {

crates/ui-egui/src/dialogs/plugin.rs

@@ -331,8 +331,8 @@ pub(crate) struct PendingInstall {
     pub approval: InstallApproval,
 }
 
-/// No OK in the shared footer: the OK in its body is a button, which Enter clicks only when it has
-/// the keyboard focus.
+/// No OK in the shared footer: the OK in its body is a `Sense::click` button, which Enter clicks
+/// only when it has the keyboard focus.
 pub(super) const INSTALL_SPEC: DialogSpec = DialogSpec {
     heading: |_| tl!("Install Plug-in…").trim_end_matches('…').to_string(),
     body_with_actions: Some(install_body),