fix piece filter with undefined choices

[ETLaurent]

Summary

What are the specific steps to test this change?

• Add the following piece to your project (add declare it in app.js)

export default {
  extend: '@apostrophecms/piece-type',
  fields: {
    add: {
      select: {
        label: 'Test',
        type: 'select',
        choices: [
          {
            label: '1',
            value: 'option1'
          },
          {
            label: '2',
            value: 'option2'
          }
        ]
      },
      checkboxes: {
        label: 'Tests',
        type: 'checkboxes',
        choices: [
          {
            label: 'A',
            value: 'optionA'
          },
          {
            label: 'B',
            value: 'optionB'
          },
          {
            label: 'C',
            value: 'optionC'
          }
        ]
      }
    },
    group: {
      basics: {
        fields: [ 'select', 'checkboxes' ]
      }
    }
  },
  filters: {
    add: {
      select: {
        label: 'Select Filter'
      },
      checkboxes: {
        label: 'Checkboxes Filter'
      }
    }
  }
};

• There should be no test: api-error: Cannot read properties of undefined (reading 'match') error and the filters should work as expected:

• without the fix, having undefined values in select or checkboxes breaks:

test: api-error: Cannot read properties of undefined (reading 'match')
 {
  module: 'test',
  type: 'api-error',
  severity: 'error',
  url: '/api/v1/test?aposMode=draft&visibility&archived=false&viewContext=manage&choices%5B0%5D=select&choices%5B1%5D=checkboxes&page=1&withPublished=1&aposLocale=en',
  path: '/api/v1/test',
  method: 'GET',
  ip: '::1',
  query: {
    aposMode: 'draft',
    visibility: null,
    archived: 'false',
    viewContext: 'manage',
    choices: [ 'select', 'checkboxes' ],
    page: '1',
    withPublished: '1',
    aposLocale: 'en'
  },
  requestId: 's2f6xxv6atu0r5qz1xtkat2n',
  name: 'error',
  status: 500,
  # ...
}

What kind of change does this PR introduce?

(Check at least one)

• Bug fix
• New feature
• Refactor
• Documentation
• Build-related changes
• Other

Make sure the PR fulfills these requirements:

• It includes a) the existing issue ID being resolved, b) a convincing reason for adding this feature, or c) a clear description of the bug it resolves
• The changelog is updated
• Related documentation has been updated
• Related tests have been updated: https://github.com/apostrophecms/testbed/pull/384

If adding a new feature without an already open issue, it's best to open a feature request issue first and wait for approval before working on it.

Other information:

[linear]

PRO-8205 Non-required `select` fields cause an error when used as a filter