Use session-specific empty state illustration for agent sessions

What does this MR do and why?

The Duo Agents Platform sessions list empty state used the generic pipelines illustration (empty-pipeline-md.svg), which is not session-specific. This MR swaps it to the new session-specific illustration empty-agent-sessions-md.svg.

The illustration was added to the gitlab-svgs package in gitlab-org/gitlab-services/design.gitlab.com!6385 (merged) and is shipped in @gitlab/svgs 3.165.0, so this MR also bumps @gitlab/svgs from 3.164.0 to 3.165.0 to make the asset available.

Element	Before	After
Empty state illustration	empty-pipeline-md.svg (generic pipelines)	empty-agent-sessions-md.svg (session-specific)
Empty state title/body	Unchanged	Unchanged

Changes:

• ee/app/assets/javascripts/ai/duo_agents_platform/components/common/agent_flow_list.vue: updated the empty-state SVG import to empty-agent-sessions-md.svg.
• package.json / yarn.lock: bumped @gitlab/svgs to 3.165.0.

agent_flow_list.vue is the only place using the pipelines illustration for this empty state, so no other components needed updating. No jest specs snapshot or assert the SVG path here (the spec only asserts svgPath is defined), so no test changes were needed.

Note: the issue also mentions the empty state having no action/learn-more link; that is out of scope for this MR, which is only the illustration swap.

References

• Related to #629857 (closed)
• Illustration added in gitlab-org/gitlab-services/design.gitlab.com!6385 (merged)

Screenshots or screen recordings

Before	After

How to set up and validate locally

For DAP/General Setup

• General DAP: https://docs.gitlab.com/development/duo_agent_platform/
• Assigning Duo to a group: https://docs.gitlab.com/development/ai_features/#run-gitlabduosetup-script
• Make sure you are in SaaS mode with export GITLAB_SIMULATE_SAAS=1 set in your env.runit file in your local gdk.

For this testing

1. Run yarn install to install @gitlab/svgs 3.165.0.
2. In a project with GitLab Duo Agent Platform enabled and no agent sessions, go to AI > Sessions.
3. Verify the empty state renders the new session-specific illustration instead of the generic pipelines illustration.

Alternatively, run the component spec:

yarn jest ee/spec/frontend/ai/duo_agents_platform/components/common/agent_flow_list_spec.js

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.