refact(angular.bind): use `concat()` rather than duplicating code

Closes #4200
feat(ngPluralize): add support for `count` to be a one-time expression

Closes #10004
fix(ngPluralize): update `whensExpFns` even if `count` is a one-time expression
fixup(ngPluralize): add support for `count` to be a one-time expression