fix(admin/view): wrap plugin history URL with basePath (#9341)

Plugin tabs/sub-tabs use history.pushState/replaceState to keep the
URL bar in sync with the active view, but updateURL fed it the raw
output of buildPluginURL ("/plugin/lanes/<lane>/..."). Under a
urlPrefix deployment that strips the prefix, so reloading the page
hit /plugin/... directly and 404'd at the proxy.

Wrap with basePath() so the rewritten URL keeps the deployment
prefix.

Reported at #9240.

weed/admin/view/app/plugin.templ

@@ -758,7 +758,7 @@ templ Plugin(page string, initialJob string, lane string) {
             }
 
             function updateURL(replace) {
-                var url = buildPluginURL(state.activeTopTab, state.activeSubTab, state.selectedJobType);
+                var url = basePath(buildPluginURL(state.activeTopTab, state.activeSubTab, state.selectedJobType));
                 if (replace) {
                     history.replaceState({ pluginTopTab: state.activeTopTab, pluginSubTab: state.activeSubTab, pluginJob: state.selectedJobType }, '', url);
                 } else {