Fix autocomplete filters showing empty values

[geetxnshgoyal]

Description

This PR fixes a bug where autocomplete filters (Projects, Packages, Creators, Reviewers, Staging Projects, and Priorities) were showing empty checkboxes after clicking the magnifier button to submit a search.

Problem

When using autocomplete filters on the requests page:

1. User types a value in an autocomplete field (e.g., Project name)
2. User clicks the magnifier (🔍) button to submit
3. Filter dropdown shows the selected value
4. User clicks magnifier again (with or without typing a new value)
5. Bug: Empty checkboxes appear in the filter dropdown

This happened because when the form was submitted, empty string values were being added to the params array and stored in @selected_filter without being cleaned up.

Solution

Modified Webui::RequestsFilter concern to use .compact_blank when assigning filter parameters to @selected_filter, ensuring empty strings are removed before rendering checkboxes in the view.

Changed methods:

• filter_creators
• filter_priorities
• filter_staging_projects
• filter_reviewers
• filter_project_names
• filter_package_names

This brings all filter methods in line with the filter_labels method, which was already correctly using compact_blank.

Testing

Added comprehensive tests in spec/controllers/webui/users/bs_requests_controller_spec.rb to verify:

• Empty strings in filter parameters are properly removed
• Valid filter values continue to work correctly
• @selected_filter hash doesn't contain empty strings
• All 6 affected filters behave consistently

Verification Steps

1. Navigate to a requests page with filters (e.g., /my/requests)
2. Open the "Projects" filter dropdown
3. Type a project name in the search box
4. Click the magnifier (🔍) button
5. Open the Projects filter dropdown again
6. Click the magnifier button again (with empty search or new value)
7. Open the Projects filter dropdown
8. Expected: Only valid project names appear as checkboxes (no empty checkboxes)
9. Repeat for Packages, Creators, Reviewers, Staging Projects, and Priorities filters

Files Changed

• app/controllers/concerns/webui/requests_filter.rb - Added .compact_blank to 6 filter methods
• spec/controllers/webui/users/bs_requests_controller_spec.rb - Added tests for empty value handling

Related Issues

Fixes #18826

[geetxnshgoyal]

@hennevogel @eduardoj please look into it :)