fix: return only the first workspace agent script timing per script (#16203)

Fixes https://github.com/coder/coder/issues/16124

If a workspace agent crashes, it is possible for any startup scripts to
be ran again. This PR makes it so that the
`GetWorkspaceAgentScriptTimingsByBuildID` query only returns the first
timing recorded per-script.

coderd/database/dbmem/dbmem.go

@@ -6388,6 +6388,15 @@ func (q *FakeQuerier) GetWorkspaceAgentScriptTimingsByBuildID(ctx context.Contex
 			WorkspaceAgentName: agent.Name,
 		})
 	}
+
+	// We want to only return the first script run for each Script ID.
+	slices.SortFunc(rows, func(a, b database.GetWorkspaceAgentScriptTimingsByBuildIDRow) int {
+		return a.StartedAt.Compare(b.StartedAt)
+	})
+	rows = slices.CompactFunc(rows, func(e1, e2 database.GetWorkspaceAgentScriptTimingsByBuildIDRow) bool {
+		return e1.ScriptID == e2.ScriptID
+	})
+
 	return rows, nil
 }