Whether Tencent buys from Tesla or from someone else doesn't matter. The increased demand pushes the share price up either way. Tesla has sold shares this year,

Whether Tencent buys from Tesla or from someone else doesn't matter. The increased demand pushes the share price up either way. Tesla has sold shares this year, and because Tencent's buy pushed the share price higher Tesla saw more proceeds from the same number of shares than they would have had Tencent not acquired a 5% stake.