Manual test collapse button has no focus indication

[mlewand]

Provide a description of the task

New focus indication has no focus indication. Since it is a button it takes the focus, but doesn't show that.

Below you can see that it can be operated with the keyboard but you wouldn't know that looking just at the screen:

[mlewand]

It's just a matter of changing

diff --git a/packages/ckeditor5-dev-tests/lib/utils/manual-tests/template.html b/packages/ckeditor5-dev-tests/lib/utils/manual-tests/template.html
index b2ea1034..c3b92586 100644
--- a/packages/ckeditor5-dev-tests/lib/utils/manual-tests/template.html
+++ b/packages/ckeditor5-dev-tests/lib/utils/manual-tests/template.html
@@ -101,12 +101,15 @@
                        border: none;
                        padding: 0;
                        margin: 0;
-                       outline: none;
                        transition: left var(--ck-manual-test-transition-time) ease-in-out;
                        opacity: .5;
                        z-index: 10000;
                }

+               .manual-test-sidebar__toggle:not(:focus) {
+                       outline: none;
+               }
+
                .manual-test-sidebar__toggle:hover {
                        opacity: 1;
                }