Implement Register Filter "Clear All" and set filter Questionnaire submit button text

[allan-on]

Feature mockup

Describe the feature request.

1. When a user clicks "Clear All", the filter Questionnaire selections should be cleared. The implementation in Add Register filtering #2698 includes the UI but no implementation for the 'Clear All' functionality.
2. The filter Questionnaire's submit button text should be updated to "Apply filters" so that this is displayed instead of 'Submit'

Additional context
See related issue #2698 for additional context
Related FHIR SDK implementations that will be used are in the following PRs

1. Allow modification of Questionnaire submit action button text via configuration google/android-fhir#2319
2. Api to clear all answers of questionnaire response. google/android-fhir#2329

Acceptance criteria

• Clicking 'Clear All' clears the filter Questionnaire selections
• The filter Questionnaire submit button text displayed is 'Apply filters'

Implementation plan (For Engineers)
The plan for implementing the solution e.g. via a description or a check list for the various ordered tasks that will need to be completed.
i.e. Describe how you intend to solve the problem