agent: Remove extraneous character in `system_prompt` template (#46238)

Release Notes:
- N/A

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Co-authored-by: Kunall Banerjee <hey@kimchiii.space>
a1bacce89aBo He committed on 1/7/2026, 9:45:16 AM· committed by GitHubparent55dc348
1 file changedLine totals unavailable