[Bug] Replacement dialog too big

[letsfindaway]

Describe the bug

The replacement dialog e.g. used on import is too big when compiling with Qt 6 (here: Qt 6.6.3). It looks fine and just takes the necessary space when compiling on Qt 5.

Screenshots

See OpenBoard-org#1311 (comment)

[letsfindaway]

Just calling resize(0, 0); after the following lines:

OpenBoard/src/document/UBDocumentController.cpp

Lines 157 to 160 in 9a884af

	mainLayout->addLayout(labelLayout);
	mainLayout->addLayout(buttonLayout);

fixes this issue.

[letsfindaway]

Seems to depend on Qt version. Not occurring with Qt 6.9.

[letsfindaway]

Previous comment was wrong. It still occurs with Qt. 6.9.1