Fix feature settings block toggle

What does this MR do and why?

There was a change to the toggle animation logic in the shared SettingsBlock component that caused a regression to the settings toggle in FeatureSettingsBlock component. This component is used in Model Selection and Duo Self-Hosted feature settings pages.

This MR resolves this regression by:

• Updating FeatureSettingsBlock to handle toggle state.
• Revert horizontal padding change for chevron icon in SettingsBlock component

References

• Chevron animation MR: Add chevron animation to a settings block (!186155 - merged)

Screenshots or screen recordings

Description	Before	After
Model selection	model_selection_before	model_selection_after
Duo Self-Hosted	duo_self_hosted_before.mov	duo_self_hosted_after.mov
SettingsBlock padding change	settings_block_before.mov	settings_block_after.mov
SettingsBlock HAML component has no regressions	settings_block_haml_before.mov	settings_block_haml_after.mov

How to set up and validate locally

Model Selection

• Run GDK on SAAS mode: GITLAB_SIMULATE_SAAS=1 gdk start
• Run the following setup script: GITLAB_SIMULATE_SAAS=1 bundle exec 'rake gitlab:duo:setup'
• Go to groups/gitlab-duo/-/settings/gitlab_duo/model_selection

Duo Self-Hosted

• You need an active online or offline, Ultimate or Premium license.
• Run GDK on non-SAAS mode: GITLAB_SIMULATE_SAAS=0 gdk start
• Run the following setup script for Duo Enterprise add-on: GITLAB_SIMULATE_SAAS=0 bundle exec 'rake gitlab:duo:setup[duo_enterprise]'
• Go to /admin/ai/duo_self_hosted/features

Settings Block

• I chose the SettingsBlock implemented within Organizations UI for this case.
• Enable the flag: ui_for_organizations
• Go to /-/organizations/default/settings/general
• Observe icon has equal padding

Settings Block HAML

• We can use the first couple settings in the Admin Settings
• Go to https://gdk.test:3443/admin/application_settings/general
• Observe no regressions to toggle animation and/or padding

MR acceptance checklist

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