R1:29e2acd5257b

Have "limit=1" tokenizers replace tokens instead of disabling "Browse"

Summary:
Fixes T9984. When a tokenizer only allows one selection (like "Task Owner:" or "Land Onto Branch:"), keep the browse button active but have it //replace// values.

Also, have "Create Subtask" default to the system default status, so subtasks of closed tasks are not also closed.

Test Plan:
- Browsed an empty limit=1 tokenizer.
- Replaced a full limit=1 tokenizer.
- Browsed an empty no-limit tokenizer.
- Browsed more…