[Studio] fix: handle partial topic batch deletion failures

[yx9o]

What is the purpose of the change

Topic batch deletion stopped at the first failed request. Topics deleted before the failure remained visible, while later selected topics were not attempted, leaving the page inconsistent with the backend state.

Brief changelog

• Continue processing the remaining topics when an individual deletion fails.
• Return successfully deleted and failed topic names separately.
• Remove only successfully deleted topics from the page.
• Keep failed topics selected for retry and show partial failure feedback.

Verifying this change

• Added service coverage for continuing after an individual deletion failure.
• Added page coverage for partial success, retained selection, and user feedback.
• Ran npm test.
• Ran npm run lint.
• Ran npm run build.
• Ran Prettier checks and git diff --check.