[Agent Builder] Fix flakey test - conversation error handling - keeps the previous conversation rounds visible when there is an error

[chrisbmar]

Summary

closes #268264

Fixes a flakey test. Ensures that before we add any optimistic round, we cancel in-flight queries. Realistically a user would need to try to send a message <200ms after a response is received for this to be the case (impossible, they can't type that fast). But, guess who can type that fast? Robots in tests.

[kibanamachine]

Flaky Test Runner Stats

🟠 Some tests failed. - kibana-flaky-test-suite-runner#12191

[✅] x-pack/platform/plugins/shared/agent_builder/test/scout_agent_builder/ui/playwright.config.ts (--arch stateful --domain classic): 50/50 tests passed.
[❌] x-pack/platform/plugins/shared/agent_builder/test/scout_agent_builder/ui/playwright.config.ts (--arch serverless --domain search): 45/50 tests passed.

see run history

[machadoum]

🚀 🚀 🚀

[kibanamachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 6e067aa

Failed CI Steps

• Scout Lane #7 - stateful-classic / default
• Scout Lane #22 - serverless-observability_complete / default

Test Failures

• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Dashboards Tab
• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Logs Tab
• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Metadata Tab
• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Metrics Tab
• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Open as page and return
• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Overview Tab - KPI charts and collapsible sections
• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Overview Tab - Services section
• [job] [logs] Scout Lane #22 - serverless-observability_complete / default / local-serverless-observability_complete - Hosts Page - Flyout - Processes Tab
• [job] [logs] Scout Lane #7 - stateful-classic / default / local-stateful-classic - APM integration not installed but setup completed - Admin user
• [job] [logs] Scout Lane #7 - stateful-classic / default / local-stateful-classic - Observability Landing Page (discover.isEsqlDefault enabled) - redirects to onboarding when no logs data exists
• [job] [logs] Scout Lane #7 - stateful-classic / default / local-stateful-classic - Profiling is not setup and no data is loaded - Admin users
• [job] [logs] Scout Lane #7 - stateful-classic / default / local-stateful-classic - Profiling is not setup and no data is loaded - Viewer users

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
agentBuilder	1.1MB	1.1MB	+49.0B

History

• 💛 Build #440090 was flaky 6d1579a
• 💔 Build #440028 failed 8c0d939

cc @chrisbmar