Explore: move items out of topnav & use canvas variant for toolbar buttons (#60630)

* Explore: remove topnav

* PageToolbar: fix left items margin when no title or page icon is set

* add missing key prop & fix tests

* use canvas variant in live logs

* avoid rendering empty space

* fix test

* avoid disabling split resize button when live tailing

* minor touchups

* Update packages/grafana-ui/src/components/PageLayout/PageToolbar.tsx

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

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

packages/grafana-ui/src/components/PageLayout/PageToolbar.tsx

@@ -190,7 +190,7 @@ const getStyles = (theme: GrafanaTheme2) => {
       min-width: 0;
     `,
     h1Styles: css`
-      margin: 0;
+      margin: ${spacing(0, 1, 0, 0)};
       line-height: inherit;
       flex-grow: 1;
       min-width: 0;
@@ -229,7 +229,7 @@ const getStyles = (theme: GrafanaTheme2) => {
       ${theme.breakpoints.up('md')} {
         align-items: center;
         display: flex;
-        padding-left: ${spacing(0.5)};
+        padding-right: ${spacing(0.5)};
       }
     `,
   };