Fix so query parameter filter=true/false enables/disables the filter bar instead of filtering by that string

[lsarni]

Description

According to the configuration documentation filter "Can be Boolean to enable or disable, or a string, in which case filtering will be enabled using that string as the filter expression."

Since url parameters are string we should compare against strings instead of booleans to check if the value is true to show the bar without filtering by any value or false to hide the bar (although it is also hidden if no parameter is set).

Motivation and Context

Fixes #6276
While testing I also realized that when filter=false instead of hiding the bar would filter by the word "false" https://petstore.swagger.io/?filter=false

How Has This Been Tested?

Locally I have tested by sending the value true, false and also other strings.

Screenshots (if appropriate):

filter=true

filter=false

filter=other-value

Checklist

My PR contains...

• No code changes (src/ is unmodified: changes to documentation, CI, metadata, etc.)
• Dependency changes (any modification to dependencies in package.json)
• Bug fixes (non-breaking change which fixes an issue)
• Improvements (misc. changes to existing features)
• Features (non-breaking change which adds functionality)

My changes...

• are breaking changes to a public API (config options, System API, major UI change, etc).
• are breaking changes to a private API (Redux, component props, utility functions, etc.).
• are breaking changes to a developer API (npm script behavior changes, new dev system dependencies, etc).
• are not breaking changes.

Documentation

• My changes do not require a change to the project documentation.
• My changes require a change to the project documentation.
• If yes to above: I have updated the documentation accordingly.

Automated tests

• My changes can not or do not need to be tested.
• My changes can and should be tested by unit and/or integration tests.
• If yes to above: I have added tests to cover my changes.
• If yes to above: I have taken care to cover edge cases in my tests.
• All new and existing tests passed.

[tim-lai]

@lsarni Thanks for the PR! However, it fails CI, specifically with test/unit/components/filter.jsx. In addition, please add Cypress tests to validate the changed behavior. Thanks.

[lsarni]

Thanks for letting me know which test was failing @tim-lai
I hadn't had time to dive into the Jenkins report. I have fixed the issue and add new cypress tests as required.

[tim-lai]

Merged! Thanks for the contribution!