Refactor deprecated object options to arrays

What does this MR do and why?

The object format for options in GlFormRadioGroup, GlFormSelect, and GlFormCheckboxGroup is deprecated, see form-options.js#L78-83. While working on a Bootstrap vue migration, gitlab-org/gitlab-services/design.gitlab.com!5836 (merged), I noticed we still use this format in 2 locations. This MR refactors those to arrays.

Replace deprecated object format `:options` props with
arrays for `gl-form-radio-group` and `gl-form-select`:

- `duo_chat_history_expiration.vue`: Convert
  `EXPIRATION_COLUMNS` from object to array
- `geo_site_form_selective_sync.vue`: Add computed
  that converts the object prop via `Object.values()`
- Update corresponding specs to match new format

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

duo_chat_history_expiration.vue

1. GDK running in Self Managed (export GITLAB_SIMULATE_SAAS=0 in env.runit file)
2. Go to Admin > Gitlab duo > Change configuration
3. Select "After the conversation was last updated" or "After the conversation was created" and save
4. Go back to same settings and verify your selection was saved

geo_site_form_selective_sync.vue

1. Apply patch

diff --git a/ee/app/assets/javascripts/geo_sites/components/app.vue b/ee/app/assets/javascripts/geo_sites/components/app.vue
index 05ec8ef2a718..3754932341ef 100644
--- a/ee/app/assets/javascripts/geo_sites/components/app.vue
+++ b/ee/app/assets/javascripts/geo_sites/components/app.vue
@@ -108,7 +108,7 @@ export default {
 
 <template>
   <section>
-    <page-heading v-if="hasSites" :heading="$options.i18n.geoSites">
+    <page-heading v-if="true" :heading="$options.i18n.geoSites">
       <template #actions>
         <gl-button
           variant="confirm"

2. Go to Admin > Geo > Sites > Add new site
3. Select different options in "Selective synchronization" dropdown and validate it changes the conditional rendering below it

All projects	Projects in certain groups	Projects in certain storage shards

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.