Remove KGlobal::locale warning for pure Qt applications

Pure Qt applications get KDE dialogs through the various KFileDialogQtOverride members, these functions instantiate a KFileDialog that inherits from KDialog so on KFileDialog construction we end up in KDialogPrivate::init that calls KDialog::setButtons that uses KStandardGuiItem::ok() that has a i18n call. Since there is no valid main component at this stage yet once we get to the fileModule() call and it creates a proper main component we will get the KGlobal::locale warning.

By invoking fileModule() before creating the KFileDialog we avoid this issue.

Acked by dfaure

REVIEW: 102188
(cherry picked from commit 6f710688154d4c9914a62f5265de09bc85e08eac)