ci: raise lua test retry timeout to 3 minutes

[Alistair-Afton]

Summary

• The Run lua tests step retries via nick-fields/retry with timeout_minutes: 1.
• Each attempt reruns the entire suite: ci/run-tests.py deletes test_status.json on startup, so --resume only helps DF restarts within an attempt, not across outer retries.
• The suite has grown enough that a full Windows run (DF boot + all tests + quit) now exceeds 60s. PR test: add in-game regression tests for five more plugins #5936 hit this: all 324 tests passed, but every attempt died at the 60s mark during shutdown, failing the job.
• Raises the per-attempt limit to 3 minutes. Worst-case wall time for a genuinely hung suite goes from 3 to 9 minutes, which is still bounded.

Test plan

• YAML parses
• Verified test: add in-game regression tests for five more plugins #5936's artifact shows the suite completing all tests before the timeout killed DF during quit

[SilasD]

this is a necessary fix now that we're actually getting some test suite coverage.

the change is minimal and looks both reasonable and correct.