Merge #16971: qt: Change default size of intro frame

8cf9898 qt: Change default size of intro frame (Emil Engler)

Pull request description:

  Because of the new pruning feature in the intro frame, the size of the intro frame is too small.
  Like you see, some text is not visible completely.

  ### Before
  ![Before](https://i.imgur.com/ppZ3Gf9.png)
  ### After
  ![After](https://i.imgur.com/wcElqLA.png)

  Update: I changed it so it adjusts the size dynamically

ACKs for top commit:
  fanquake:
    ACK 8cf9898 - Before and after macOS screens below. Given that most users will only ever see this screen once, I think Qts best effort to dynamically size it is fine.
  jonasschnelli:
    utACK 8cf9898
  Sjors:
    Tested ACK 8cf9898 on macOS. English already fit, so to reproduce the issue, launch in German with `-resetguisettings -lang=de`.
  laanwj:
    ACK 8cf9898

Tree-SHA512: 568b0ae0d5feeda603c0ccf67b5bb3857becea8f22fb98695e1901e662cb1e76377589e39ec743258154d7f6c4a5e544bb003fcc73597400dd427db047392638

Author: laanwj

src/qt/intro.cpp

@@ -154,6 +154,7 @@ Intro::Intro(QWidget *parent, uint64_t blockchain_size, uint64_t chain_state_siz
         storageRequiresMsg.arg(requiredSpace) + " " +
         tr("The wallet will also be stored in this directory.")
     );
+    this->adjustSize();
     startThread();
 }