chore: remove ai summary from discussion thread

[nickoferrall]

Fix #8858

This PR doesn't remove the discussion summary from the meeting summary. This will be handled in a separate issue: #9710

To test

• Create a retro and have a group with two or more reflections
• See the AI discussion suggestion in the discussion thread, but not the AI Summary

[Dschoordsch]

Now we only have the discussion prompt questions, also on the summary. I think we've discussed once that it might make sense to keep the questions in the meeting, but the summary for the groups in the meeting summary.

[nickoferrall]

For sure! This PR (#9711) removes the discussion prompts from the meeting summary