swaps operator from equals to contains when you start typing text to equal

[areisle]

Describe the bug
when you start typing text to search and have already select equals as the operator, it swaps itself back to contains

To Reproduce

1. got to advanced query page
2. select 'Therapy
3. select equals
4. type text to search

Expected behaviour
it should not change from equals to contains

Versions (please complete the following information):
tested on dev deployment https://graphkbdev.bcgsc.ca/query-advanced in chrome

• Version: dev (f72972b