Support no label/assignee filter and batch clearing labels/assignees (#24707)

Since milestones has been implemented, this PR will fix #3407

---------

Co-authored-by: Jason Song <i@wolfogre.com>

options/locale/locale_en-US.ini

@@ -1361,6 +1361,7 @@ issues.delete_branch_at = `deleted branch <b>%s</b> %s`
 issues.filter_label = Label
 issues.filter_label_exclude = `Use <code>alt</code> + <code>click/enter</code> to exclude labels`
 issues.filter_label_no_select = All labels
+issues.filter_label_select_no_label = No Label
 issues.filter_milestone = Milestone
 issues.filter_milestone_all = All milestones
 issues.filter_milestone_none = No milestones
@@ -1371,6 +1372,7 @@ issues.filter_project_all = All projects
 issues.filter_project_none = No project
 issues.filter_assignee = Assignee
 issues.filter_assginee_no_select = All assignees
+issues.filter_assginee_no_assignee = No assignee
 issues.filter_poster = Author
 issues.filter_poster_no_select = All authors
 issues.filter_type = Type