Switching between date filter widget type in field filters show NaN dates

[paoliniluis]

Describe the bug
When switching the filter widget type in date field filters makes the filter to show invalid dates. For example: switching between a date range filter and single date.

Logs
Seems like a frontend issue only:

Deprecation warning: value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are discouraged and will be removed in an upcoming major release. Please refer to http://momentjs.com/guides/#/warnings/js-date/ for more info.
Arguments: 
[0] _isAMomentObject: true, _isUTC: false, _useUTC: false, _l: undefined, _i: 2019-09-07~2019-09-30, _f: undefined, _strict: undefined, _locale: [object Object]

To Reproduce

1. Build a native sql query on the sample dataset:

SELECT * FROM ORDERS WHERE {{date}}

2. set the date filter as a field filter to the date field of the orders table. Set the type as a range type
3. set the filter to a range like Oct-1-2019 / Oct-30-2019
4. change the filter type to a single date type

Expected behavior
Filter to be cleared so user can input a date and does not see an error

Screenshots

Information about your Metabase Installation:

• Your browser and the version: Brave latest
• Your operating system: Ubuntu LTS latest
• Your databases: Sample
• Metabase version: 0.39.4
• Metabase hosting environment: Docker
• Metabase internal database: Postgres

Severity
Not severe, a FE glitch that can be bypassed by clicking on the cross and cleaning the filter

Additional context
None